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Ten Facts about Pi

Date: 09/15/2002 at 20:42:09
From: Christy
Subject: Ten facts about pi

I know nothing about pi. I'm supposed to research 10 facts about pi. 

Thank you.


Date: 09/18/2002 at 21:18:46
From: Doctor Nitrogen
Subject: Re: Ten facts about pi

Hi Christy,

Here are ten facts about pi:

1. Pi is used to calculate the area and volumes of a wide variety 
   of  two-dimensional and three-dimensional geometrical objects.  
   To see what some of them are, you can go to the Geometric Formulas 
   section of the Dr. Math FAQ:

   http://mathforum.org/dr.math/faq/formulas/ 

   Look under Circle, Cone, and Sphere for starters. 

2. The decimal expansion of pi never terminates.


3. One area of mathematical interest is computing pi to as many 
   decimals as a computer can handle.  At 

   PiHex - A distributed effort to calculate Pi
   http://www.cecm.sfu.ca/projects/pihex/ 

   you can find various "distributed computing" projects where pi was 
   calculated for huge numbers of decimal digits. One such project you 
   will see there calculated pi up to 40 trillion decimal digits.

4. Throughout history, various civilizations obtained different 
   values for pi. For instance, in the Bible, the Israelites 
   approximated pi simply as the number 3. The ancient Greek 
   scientist Archimedes also got several approximations for pi.

5. There was a British mathematician named Hardy who was a kind of 
   "sponsor" of Srinivasa Ramanujan, a man who came up with cool 
   formulas by which pi could be quickly calculated.

6. Pi is used extensively in trigonometry.

7. Pi is used extensively by scientists and engineers. 

8. There are circles you can draw on the surface of a sphere for which 
   the ratio of the circumference of that circle to its diameter will 
   not equal pi. This gets into General Relativity Theory. You can 
   read more about this in the Dr. Math archives:

   Einstein, Curved Space, and Pi
   http://mathforum.org/library/drmath/view/55198.html 

9. If you try to draw a circle on a saddle surface, the ratio of 
   the circumference to the diameter will also not equal pi, for a 
   similar reason as applies in (8) above.

10. Pi will never be the root of any polynomial equation. 

I hope this helps! For general information about pi, see the Dr. Math 
FAQ:

   About Pi
   http://mathforum.org/dr.math/faq/faq.pi.html 

- Doctors Nitrogen and Sarah, The Math Forum
  http://mathforum.org/dr.math/ 
Associated Topics:
Middle School Pi

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