[AT] Supposedly why our old tractors are not metric and a fairly simple tutorial

[James Peck]

I took Thermodynamics is a classroom with a 6 foot wooden slide rule suspended above the blackboard. The instructor would always estimate the answer before he brought the slide rule into play. He estimate was usually within 10% or less of the slide rule calculation.

He would use 10 as a value for pi squared.

Scientific calculators were still 10 years from affordability for personal use.
________________________________
From: AT <at-bounces at lists.antique-tractor.com> on behalf of Carl Gogol <cgogol1971 at gmail.com>
Sent: Friday, March 6, 2020 9:21 AM
To: 'Antique Tractor Email Discussion Group' <at at lists.antique-tractor.com>
Subject: Re: [AT] Supposedly why our old tractors are not metric and a fairly simple tutorial

The context I learned 22/7 was in high school math.  Lots of simple problems
could be built around  it.  I have never heard of the 355/113 version.
Carl
Manlius, NY

-----Original Message-----
From: AT <at-bounces at lists.antique-tractor.com> On Behalf Of Roger Moffat
Sent: Thursday, March 5, 2020 8:34 PM
To: Antique Tractor Email Discussion Group <at at lists.antique-tractor.com>
Subject: Re: [AT] Supposedly why our old tractors are not metric and a
fairly simple tutorial



> On Feb 25, 2020, at 9:58 AM, Stephen Offiler <soffiler at gmail.com> wrote:
>
> Just a matter of significant digits.  22/7 is about 0.04% higher than the
"true" value of pi.  That's pretty darn good for many practical purposes,
but I wouldn't want to be calculating a moon launch with that kind of error.

An even more accurate, easy to remember value for pi is 355/113 (or 113
divided into 355)

22/7 = 3.14285714
pi = 3.1415926535
355/113 = 3.14159292

Cheers

Roger
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