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Re: Merry Christmas!

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  Re: Merry Christmas! David Ryeburn <david_ryeburn@telus.netz> - 2017-01-07 17:23 -0800
    Re: Merry Christmas! dorayme <do_ray_me@bigpond.com> - 2017-01-08 14:03 +1100
      Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 13:35 -0500
        Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-09 05:42 +1100
        Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-08 20:01 +0000
          Re: Merry Christmas! Tim Streater <timstreater@greenbee.net> - 2017-01-08 22:48 +0000
            Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 02:05 +0000
          Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-09 15:52 -0500
        Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-08 21:44 -0500
          Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-09 14:27 +1100
          Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 12:06 +0000
            Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-09 19:16 -0500
              Re: Merry Christmas! Your Name <YourName@YourISP.com> - 2017-01-10 13:39 +1300
        Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-14 23:17 -0500
    Re: Merry Christmas! Davoud <star@sky.net> - 2017-01-08 01:41 -0500
      Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-08 06:55 +0000
        Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 17:24 -0500
      Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-08 11:38 -0500
        Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-08 09:18 -0800
          Re: Merry Christmas! AL <45364747@invalid.com> - 2017-01-08 11:03 -0700
            Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-08 19:35 +0000
            Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-08 14:05 -0800
              Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 17:56 -0500
                Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-08 15:21 -0800
                  Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 21:15 -0500
                    Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 02:45 +0000
                      Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 22:18 -0500
                      Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-09 16:40 -0500
                        Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-14 23:35 -0500
                          Re: Merry Christmas! Alan Baker <alangbaker@telus.net> - 2017-01-14 21:56 -0800
                          Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-15 08:30 -0500
                Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 02:25 +0000
                  Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 22:08 -0500
                    Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 12:01 +0000
                      Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-09 18:15 -0500
                        Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-09 20:07 -0500
                        Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-10 05:26 +0000
                    Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-09 20:04 -0500
                      Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-10 00:08 -0500
                        Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-10 18:44 -0500
                          Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-11 17:06 -0500
                            Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-12 08:11 -0500
                            Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-12 16:02 -0500
                        Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-15 00:30 -0500
                          Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-16 02:20 -0500
                            Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-16 16:34 -0500
                              Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-16 18:18 -0500
                                Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-16 18:16 -0800
                                  Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-17 00:01 -0500
                                  Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-17 07:49 -0500
                                Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-17 07:44 -0500
                                  Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-17 15:57 -0500
                                    Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-17 19:00 -0500
                                      Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-17 23:40 -0500
                                        Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-20 16:07 -0500
                                          Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-20 18:39 -0500
                                            Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-21 08:01 -0500
                                            Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-22 08:13 +1100
                                              Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-21 17:40 -0500
                                                Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-22 21:03 +1100
                                                Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-22 08:32 -0500
                                                  Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-22 14:32 -0500
                                                    Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-23 15:55 -0500
                                  Re: Merry Christmas! Savageduck <savageduck1@{REMOVESPAM}me.com> - 2017-01-17 16:51 -0600
                                    Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-17 18:57 -0500
                                    Re: Merry Christmas! martin <martin@rakupottery.org.uk> - 2017-01-17 23:15 +0000
                            Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-18 20:02 +0100
                              Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-18 15:29 -0500
                                Re: Merry Christmas! Your Name <YourName@YourISP.com> - 2017-01-20 09:28 +1300
                                  Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-20 16:15 -0500
                                Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-20 19:17 +0100
                              Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-20 16:08 -0500
                                Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-21 01:39 +0100
                                  Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-21 08:03 -0500
                                    Re: Merry Christmas! sms <scharf.steven@geemail.com> - 2017-01-21 08:04 -0800
                                      Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-21 13:07 -0500
                                        Re: Merry Christmas! sms <scharf.steven@geemail.com> - 2017-01-21 11:21 -0800
                                          Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-22 08:22 -0500
                                      Re: Merry Christmas! nospam <nospam@nospam.invalid> - 2017-01-21 13:09 -0500
                                      Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-27 00:12 +0100
                                        Re: Merry Christmas! sms <scharf.steven@geemail.com> - 2017-01-26 17:21 -0800
                                          Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-26 20:26 -0500
                    Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-14 23:54 -0500
              Re: Merry Christmas! AL <45364747@invalid.com> - 2017-01-08 16:11 -0700
                Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-08 15:26 -0800
                  Re: Merry Christmas! AL <45364747@invalid.com> - 2017-01-08 23:26 -0700
                    Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 12:10 +0000
                      Re: Merry Christmas! AL <4567784747@invalid.com> - 2017-01-09 08:46 -0700
                        Re: Merry Christmas! Your Name <YourName@YourISP.com> - 2017-01-10 08:48 +1300
                        Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 20:22 +0000
                      Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-09 18:22 -0500
                        Re: Merry Christmas! Your Name <YourName@YourISP.com> - 2017-01-10 13:20 +1300
                        Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-10 05:33 +0000
                          Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-10 05:36 +0000
                Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 02:33 +0000
        Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 14:19 -0500
          Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-08 19:36 +0000
            Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-08 21:18 -0500
          Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-09 07:23 +1100
          Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-15 00:38 -0500
    Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-08 22:01 -0500
    Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-14 23:03 -0500

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#98377 — Re: Merry Christmas!

In article <o4qa74$ak6$1@dont-email.me>,
 Thomas Stein <tstein@tstein.net> wrote:

> https://www.biblegateway.com/passage/?search=1+Kings+7%3A23&version=KJV
> 
> Given the measurements there, Pi would have to be three
> 
> - a "molten sea" (kind of a bowl, kettle or cauldron I guess) which is
> "round all about"
> - diameter "10 cubits from one brim to the other"
> - circumference "a line of thirty cubits"
> 
> As Pi is defined as circumference of a circle divided by the diameter of
> the same circle -> 30 by 10 equals 3


One mathematically consistent explanation might be that in those times 
people didn't know about circles and instead used regular hexagons, for 
which the ratio of perimeter to diameter is indeed exactly 3. Gives a 
new meaning to the expression "rough riders".

-- 
David Ryeburn
david_ryeburn@telus.netz
To send e-mail, change "netz" to "net"

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#98380

In article 
<david_ryeburn-E03E33.17232407012017@88-209-239-213.giganet.hu>,
 David Ryeburn <david_ryeburn@telus.netz> wrote:

> In article <o4qa74$ak6$1@dont-email.me>,
>  Thomas Stein <tstein@tstein.net> wrote:
> 
> > https://www.biblegateway.com/passage/?search=1+Kings+7%3A23&version=KJV
> > 
> > Given the measurements there, Pi would have to be three
> > 
> > - a "molten sea" (kind of a bowl, kettle or cauldron I guess) which is
> > "round all about"
> > - diameter "10 cubits from one brim to the other"
> > - circumference "a line of thirty cubits"
> > 
> > As Pi is defined as circumference of a circle divided by the diameter of
> > the same circle -> 30 by 10 equals 3
> 
> 
> One mathematically consistent explanation might be that in those times 
> people didn't know about circles and instead used regular hexagons, for 
> which the ratio of perimeter to diameter is indeed exactly 3. Gives a 
> new meaning to the expression "rough riders"

I think the concept of a circle as being *smoothly* curved was well 
grasped. As for calculating stuff about them, that is a different 
matter and approximations using polygons might well have been a 
method.

-- 
dorayme

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#98404

On 2017-01-07 22:03, dorayme wrote:

> I think the concept of a circle as being *smoothly* curved was well 
> grasped. As for calculating stuff about them, that is a different 
> matter and approximations using polygons might well have been a 
> method.


So, this caused me to read up on Pi.  Like me, it is an irrational
number :-)

By 5th cetury AD, Chinese and Indians have gotted it to 7 decimals.

And Pythagoras lived also about 5th century BC (570 to 495 according to
Wikipedia).

Considering that the earth was still flat at the time, I am somewhat
curious on what people of 5 centuries AD would need to calculate
circumference so precisely for. It wasn't until much later that the flat
earth got inflated into a spherical ball, at which point circle
calculations become quite important for navigation.



Pyramids weren't round. And lining a wheel with a metal strip, you'd
just roll the strip around the wheel and cut it to fit visually and then
nail it to the rim of wheel.

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#98405

"JF Mezei" <jfmezei.spamnot@vaxination.ca> wrote in message 
news:58728655$0$1522$c3e8da3$12bcf670@news.astraweb.com...
> On 2017-01-07 22:03, dorayme wrote:
>
>> I think the concept of a circle as being *smoothly* curved was well
>> grasped. As for calculating stuff about them, that is a different
>> matter and approximations using polygons might well have been a
>> method.
>
>
> So, this caused me to read up on Pi.  Like me, it is an irrational
> number :-)
>
> By 5th cetury AD, Chinese and Indians have gotted it to 7 decimals.
>
> And Pythagoras lived also about 5th century BC (570 to 495 according to
> Wikipedia).
>
> Considering that the earth was still flat at the time, I am somewhat
> curious on what people of 5 centuries AD would need to calculate
> circumference so precisely for. It wasn't until much later that the flat
> earth got inflated into a spherical ball, at which point circle
> calculations become quite important for navigation.

But the earth wasn’t the only close to round thing around that the time.

> Pyramids weren't round.

But some granaries were because they were stronger that way.

> And lining a wheel with a metal strip, you'd just roll the strip around
> the wheel and cut it to fit visually and then nail it to the rim of wheel.

But you might want to know the capacity of a round granary
or water tank etc. 

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#98412

In message <58728655$0$1522$c3e8da3$12bcf670@news.astraweb.com> 
  JF Mezei <jfmezei.spamnot@vaxination.ca> wrote:
> On 2017-01-07 22:03, dorayme wrote:

>> I think the concept of a circle as being *smoothly* curved was well 
>> grasped. As for calculating stuff about them, that is a different 
>> matter and approximations using polygons might well have been a 
>> method.


> So, this caused me to read up on Pi.  Like me, it is an irrational
> number :-)

> By 5th cetury AD, Chinese and Indians have gotted it to 7 decimals.

> And Pythagoras lived also about 5th century BC (570 to 495 according to
> Wikipedia).

> Considering that the earth was still flat at the time,

No, it was not. Only in mythology was the Earth flat.

> I am somewhat curious on what people of 5 centuries AD would need to
> calculate circumference so precisely for. It wasn't until much later
> that the flat earth got inflated into a spherical ball, at which point
> circle calculations become quite important for navigation.

None of this is accurate. At all.

The precision of pi is largely meaningless. Even when calculating the
orbits of the planets we only need a handful of decimals. No one before
the space age needed 7 digits of precision, it was simply a mathematical
exercise.

NASA and JPL use "3.141592653589793" for Pi. With a orbit of radius 20
billion km, the 15 digits gives a precision of ± 2cm.

20 billion km is more than four times the distance from the sun to
Neptune.

The Earth is only 150 million km from the sun, and 3.1415926 is enough
to calculate the orbit of the earth to less than one mm.

Pi to 40 digits is enough precision to measure the circumference of the
entire known universe to ± one atom of hydrogen.

Look at it this way, you have a decent sized park that is circular. The
park is 1000 meters in diameter. When you order the fencing for it, do
you order 3143 meters of fence, or do you order 3141.592653589793 meters
of fence?

22/7 gives you 3143 meters of fence.

That's almost two miles of fence, and 22/7 gives you an answer within
1.41 meters (<5 feet).

Is 22/7 enough for building a bridge across the Hudson river? No, but
3.1416 probably is.

-- 
Major Strasser has been shot. Round up the usual suspects.

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#98424

In article <slrno756o6.14au.g.kreme@snow.local>, Lewis
<g.kreme@gmail.com.dontsendmecopies> wrote:

>In message <58728655$0$1522$c3e8da3$12bcf670@news.astraweb.com> 
>  JF Mezei <jfmezei.spamnot@vaxination.ca> wrote:
>> On 2017-01-07 22:03, dorayme wrote:
>
>>> I think the concept of a circle as being *smoothly* curved was well 
>>> grasped. As for calculating stuff about them, that is a different 
>>> matter and approximations using polygons might well have been a 
>>> method.
>
>
>> So, this caused me to read up on Pi.  Like me, it is an irrational
>> number :-)
>
>> By 5th cetury AD, Chinese and Indians have gotted it to 7 decimals.
>
>> And Pythagoras lived also about 5th century BC (570 to 495 according to
>> Wikipedia).
>
>> Considering that the earth was still flat at the time,
>
>No, it was not. Only in mythology was the Earth flat.
>
>> I am somewhat curious on what people of 5 centuries AD would need to
>> calculate circumference so precisely for. It wasn't until much later
>> that the flat earth got inflated into a spherical ball, at which point
>> circle calculations become quite important for navigation.
>
>None of this is accurate. At all.
>
>The precision of pi is largely meaningless.

[snip dissertation of digits of pi]

Yeah, we know all this. So your point is what, precisely (to 40 digits,
please)?

-- 
New Socialism consists essentially in being seen to have your heart in 
the right place whilst your head is in the clouds and your hand is in 
someone else's pocket.

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#98436

In message <080120172248394313%timstreater@greenbee.net> Tim Streater <timstreater@greenbee.net> wrote:
> Yeah, we know all this.

I doubt that very much. I see people every day using 10 digits of
"precision" when making calculations with pi because "that's what the
calculator said".

-- 
On 30 Jul 2013, Wietse Venema wrote:
>Think 100MHz Pentium, 33k6 analog modem. Even I have stopped using that.

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#98498

On 2017-01-08 15:01, Lewis wrote:

>
> NASA and JPL use "3.141592653589793" for Pi. With a orbit of radius 20

GPS doesn't even use "that" accurate value for π.

			3.1415926535898

Or 2 orders less precision.

That is what the entire GPS ground, space and user segments are supposed 
to use for π in computing any orbital intermediate or final values. 
Indeed using a more accurate value could result in errors in computing 
the positions of satellites and thus the user PVT.

(Once PVT is computed the user segment equipment can then use any value 
of π it likes of course...)

-- 
"If war is God's way of teaching Americans geography, then
recession is His way of teaching everyone a little economics."
   ..Raj Patel, The Value of Nothing.

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#98441

On 1/8/17 1:35 PM, JF Mezei wrote:
> Considering that the earth was still flat at the time, I am somewhat
> curious on what people of 5 centuries AD would need to calculate
> circumference so precisely for. It wasn't until much later that the flat
> earth got inflated into a spherical ball, at which point circle
> calculations become quite important for navigation.

It wasn't until the Greek fanatic began closing in on pi that they began 
measuring the corners of a triangle as angles relative to circumference.

Angles help surveyors record property markers in metes and bounds. The 
less precise pi is, the farther surveys may differ in where they say a 
property marker should be.  If the difference is 10 meters, that means 
war.  If, due to the precision of pi, it's only 10 millimeters, the 
United Nations can probably settle it.

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#98450

"John Somerset" <somerset@nospam.com> wrote in message 
news:o4utc0$ulp$1@dont-email.me...
> On 1/8/17 1:35 PM, JF Mezei wrote:
>> Considering that the earth was still flat at the time, I am somewhat
>> curious on what people of 5 centuries AD would need to calculate
>> circumference so precisely for. It wasn't until much later that the flat
>> earth got inflated into a spherical ball, at which point circle
>> calculations become quite important for navigation.
>
> It wasn't until the Greek fanatic began closing in on pi that they began 
> measuring the corners of a triangle as angles relative to circumference.
>
> Angles help surveyors record property markers in metes and bounds. The 
> less precise pi is, the farther surveys may differ in where they say a 
> property marker should be.  If the difference is 10 meters, that means 
> war.

Have fun listing even a single example of a difference of 10 meters 
producing war.

> If, due to the precision of pi, it's only 10 millimeters, the United 
> Nations can probably settle it.

Even sillier than you usually manage. 

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#98467

In message <o4utc0$ulp$1@dont-email.me> 
  John Somerset <somerset@nospam.com> wrote:
> On 1/8/17 1:35 PM, JF Mezei wrote:
>> Considering that the earth was still flat at the time, I am somewhat
>> curious on what people of 5 centuries AD would need to calculate
>> circumference so precisely for. It wasn't until much later that the flat
>> earth got inflated into a spherical ball, at which point circle
>> calculations become quite important for navigation.

> It wasn't until the Greek fanatic began closing in on pi that they began 
> measuring the corners of a triangle as angles relative to circumference.

> Angles help surveyors record property markers in metes and bounds. The 
> less precise pi is, the farther surveys may differ in where they say a 
> property marker should be.  If the difference is 10 meters, that means 
> war.  If, due to the precision of pi, it's only 10 millimeters, the 
> United Nations can probably settle it.

No one lays out a single survey the size of a continent, so the margin
of error for a 1000m square survey needs 3.1416 at most, as that will
give a precision of a cm or so.

-- 
NO ONE WANTS TO HEAR ABOUT MY SCIATICA Bart chalkboard Ep. AABF09

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#98505

On 1/9/17 7:06 AM, Lewis wrote:
> In message <o4utc0$ulp$1@dont-email.me>
>    John Somerset <somerset@nospam.com> wrote:
>> On 1/8/17 1:35 PM, JF Mezei wrote:
>>> Considering that the earth was still flat at the time, I am somewhat
>>> curious on what people of 5 centuries AD would need to calculate
>>> circumference so precisely for. It wasn't until much later that the flat
>>> earth got inflated into a spherical ball, at which point circle
>>> calculations become quite important for navigation.
>
>> It wasn't until the Greek fanatic began closing in on pi that they began
>> measuring the corners of a triangle as angles relative to circumference.
>
>> Angles help surveyors record property markers in metes and bounds. The
>> less precise pi is, the farther surveys may differ in where they say a
>> property marker should be.  If the difference is 10 meters, that means
>> war.  If, due to the precision of pi, it's only 10 millimeters, the
>> United Nations can probably settle it.
>
> No one lays out a single survey the size of a continent, so the margin
> of error for a 1000m square survey needs 3.1416 at most, as that will
> give a precision of a cm or so.
>
Yep, we owe that precision to the Greek pi fanatic whose name I forgot.

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#98508

In article <o51920$p9$1@dont-email.me>, John Somerset
<somerset@nospam.com> wrote:
> On 1/9/17 7:06 AM, Lewis wrote:
> > In message <o4utc0$ulp$1@dont-email.me>
> >    John Somerset <somerset@nospam.com> wrote:
> >> On 1/8/17 1:35 PM, JF Mezei wrote:
> >>> Considering that the earth was still flat at the time, I am somewhat
> >>> curious on what people of 5 centuries AD would need to calculate
> >>> circumference so precisely for. It wasn't until much later that the flat
> >>> earth got inflated into a spherical ball, at which point circle
> >>> calculations become quite important for navigation.
> >
> >> It wasn't until the Greek fanatic began closing in on pi that they began
> >> measuring the corners of a triangle as angles relative to circumference.
> >
> >> Angles help surveyors record property markers in metes and bounds. The
> >> less precise pi is, the farther surveys may differ in where they say a
> >> property marker should be.  If the difference is 10 meters, that means
> >> war.  If, due to the precision of pi, it's only 10 millimeters, the
> >> United Nations can probably settle it.
> >
> > No one lays out a single survey the size of a continent, so the margin
> > of error for a 1000m square survey needs 3.1416 at most, as that will
> > give a precision of a cm or so.
> 
> Yep, we owe that precision to the Greek pi fanatic whose name I forgot.

His name was Apple ... Apple Pi.   ;-)

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#98659

On 01-08-2017 13:35, JF Mezei wrote:
> And Pythagoras lived also about 5th century BC (570 to 495 according to
> Wikipedia).
>
> Considering that the earth was still flat at the time, I am somewhat
> curious on what people of 5 centuries AD would need to calculate
> circumference so precisely for. It wasn't until much later that the flat
> earth got inflated into a spherical ball, at which point circle
> calculations become quite important for navigation.

A lot of people knew the earth was not flat LONG before Columbus.
Eratosthenes estimated the circumference around 200 BC.
Spherical earth was the consensus of Greek scholars
in the fifth century BC

<https://books.google.com/books?id=DmK4AAAAIAAJ&q=spherical+earth>

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#98389

Thomas Stein:
> > https://www.biblegateway.com/passage/?search=1+Kings+7%3A23&version=KJV

> > Given the measurements there, Pi would have to be three
> > 
> > - a "molten sea" (kind of a bowl, kettle or cauldron I guess) which is
> > "round all about"
> > - diameter "10 cubits from one brim to the other"
> > - circumference "a line of thirty cubits"
> > 
> > As Pi is defined as circumference of a circle divided by the diameter of
> > the same circle -> 30 by 10 equals 3

David Ryeburn:
> One mathematically consistent explanation might be that in those times 
> people didn't know about circles and instead used regular hexagons, for 
> which the ratio of perimeter to diameter is indeed exactly 3. Gives a 
> new meaning to the expression "rough riders".

But not consistent with known history. First we have the Sun and Moon,
observed to be circles by the earliest modern humans, at least 100,000
years BP. That a round object in the form of a section of a tree trunk
or perhaps a round stone could be rolled no doubt goes back in deep
prehistory. That such a round shape could be made useful by making a
hole in it and attaching an axle goes back to the era between about
4500 and 3300 BCE in the form of potter's wheels and wagon wheels
(wooden discs with holes for axles), well before the emergence of the
Jewish people. The wheel is a discovery--the discovery that round
objects could be made to do work--rather than an invention. And the
method of using a drawing compass or similar tool to draw an accurate
circle also dates from antiquity.

As for Pi, many of the peoples (Chinese, Egyptians, Babylonians) who
knew how to make use of the value did not have a way of accurately
calculating the value or a notation in which to write it with accuracy.
It didn't matter; the case in which I am familiar, numerous
measurements in the engineering and architecture of ancient Egyptian
structures, reveals that the Egyptians knew how to use Pi, if not how
to write it down.

-- 
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

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#98390

In message <080120170141296820%star@sky.net> 
  Davoud <star@sky.net> wrote:
> Thomas Stein:
>> > https://www.biblegateway.com/passage/?search=1+Kings+7%3A23&version=KJV

>> > Given the measurements there, Pi would have to be three
>> > 
>> > - a "molten sea" (kind of a bowl, kettle or cauldron I guess) which is
>> > "round all about"
>> > - diameter "10 cubits from one brim to the other"
>> > - circumference "a line of thirty cubits"
>> > 
>> > As Pi is defined as circumference of a circle divided by the diameter of
>> > the same circle -> 30 by 10 equals 3

> David Ryeburn:
>> One mathematically consistent explanation might be that in those times 
>> people didn't know about circles and instead used regular hexagons, for 
>> which the ratio of perimeter to diameter is indeed exactly 3. Gives a 
>> new meaning to the expression "rough riders".

> But not consistent with known history. First we have the Sun and Moon,
> observed to be circles by the earliest modern humans, at least 100,000
> years BP. That a round object in the form of a section of a tree trunk
> or perhaps a round stone could be rolled no doubt goes back in deep
> prehistory. That such a round shape could be made useful by making a
> hole in it and attaching an axle goes back to the era between about
> 4500 and 3300 BCE in the form of potter's wheels and wagon wheels
> (wooden discs with holes for axles), well before the emergence of the
> Jewish people. The wheel is a discovery--the discovery that round
> objects could be made to do work--rather than an invention. And the
> method of using a drawing compass or similar tool to draw an accurate
> circle also dates from antiquity.

A round piece of wood with a hole and an axle isn't a wheel, it's a
round piece of wood that will very quickly fall to pieces.

A wheel is a manufactured (and invented) tool, it requires more than
some Flintstone's cartoon chunk of wood.

> As for Pi, many of the peoples (Chinese, Egyptians, Babylonians) who
> knew how to make use of the value did not have a way of accurately
> calculating the value or a notation in which to write it with accuracy.

With enough accuracy to build? Certainly. You only need 3.14-ish for
almost anything. 22/7 is close enough for almost everything no involving
ballistics or orbits.

-- 
They say only the good die young. If it works the other way too I'm
immortal

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#98423

On 2017-01-08 01:55, Lewis wrote:

> A wheel is a manufactured (and invented) tool, it requires more than
> some Flintstone's cartoon chunk of wood.

You've obnviously never read up on your history.
http://img.timeinc.net/time/photoessays/2008/10_cars/flintstones.jpg

Flintstones cars had cylindrical wheels made of rock. More akin to a
steam roller than a car. They did have a wooden axle though which
provided the interface to the car frame. (It is not clear how the rear
wheels stayed attached when moving forwards, or how the front wheel
stayed attached when moving backwards).

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#98401

On 1/8/17 1:41 AM, Davoud wrote:
> As for Pi, many of the peoples (Chinese, Egyptians, Babylonians) who
> knew how to make use of the value did not have a way of accurately
> calculating the value or a notation in which to write it with accuracy.
> It didn't matter; the case in which I am familiar, numerous
> measurements in the engineering and architecture of ancient Egyptian
> structures, reveals that the Egyptians knew how to use Pi, if not how
> to write it down.

In Egypt, the Rhind Papyrus came from about 1650 BC.  Problem 41 tells 
how to compute the volume of a cylindrical granary:
V= [(1-1/9)d]^2 h

Problem 48 says that the area of a circle is 64/81 that of the 
circumscribing square.

Both say pi is 3.16.  Contemporary Babylonians said 3.125. Solomon was 
wise enough to settle quarrels between ladies by splitting babies. He 
must have been wise enough to split the difference between his 
neighbors.  That would have yielded 3.1425.

I have it!  The wall of the casting was 4" thick.  Inside circumference: 
30 cubits.  Outside diameter: 10 cubits!

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#98402

In article <o4tps3$dr5$1@dont-email.me>,
 John Somerset <somerset@nospam.com> wrote:

> On 1/8/17 1:41 AM, Davoud wrote:
> > As for Pi, many of the peoples (Chinese, Egyptians, Babylonians) who
> > knew how to make use of the value did not have a way of accurately
> > calculating the value or a notation in which to write it with accuracy.
> > It didn't matter; the case in which I am familiar, numerous
> > measurements in the engineering and architecture of ancient Egyptian
> > structures, reveals that the Egyptians knew how to use Pi, if not how
> > to write it down.
> 
> In Egypt, the Rhind Papyrus came from about 1650 BC.  Problem 41 tells 
> how to compute the volume of a cylindrical granary:
> V= [(1-1/9)d]^2 h
> 
> Problem 48 says that the area of a circle is 64/81 that of the 
> circumscribing square.
> 
> Both say pi is 3.16.  Contemporary Babylonians said 3.125. Solomon was 
> wise enough to settle quarrels between ladies by splitting babies. He 
> must have been wise enough to split the difference between his 
> neighbors.  That would have yielded 3.1425.
> 
> I have it!  The wall of the casting was 4" thick.  Inside circumference: 
> 30 cubits.  Outside diameter: 10 cubits!


As to the accuracy of pi, as figured by "whoever", using whatever 
method...

Not being a mathematician, I can't speak to how true/accurate it is, but 
over the years, I've repeatedly bumped into claims that if pi to 4 
digits were to be used on scales of light-years, the error from such 
"inaccuracy" will fit on a yardstick, to 6 digits, and you can measure 
the error on a kid's school ruler, and at 8 significant digits, you 
start expressing the error in terms of a few dozen atom-widths. 

My point (and that of those making the claims as I've encountered them) 
being: in the real world (as opposed to "pure math"), "pi = ~3.14" is 
almost certainly adequate for all but the most nit-picky applications.

-- 
Brought to you by the letter K and the number .357
Security provided by Horace S. & Dan W.

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#98403

On 1/8/2017 10:18 AM, Don Bruder wrote:

> in the real world (as opposed to "pure math"), "pi = ~3.14" is almost
> certainly adequate for all but the most nit-picky applications.

In the real world? These days most of us non-math people would probably
use our phone for any calculations. The generic Calculator app that came
on my phone has pi out to 11 places...

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