Drexel dragonThe Math ForumDonate to the Math Forum

Ask Dr. Math - Questions and Answers from our Archives
_____________________________________________
Associated Topics || Dr. Math Home || Search Dr. Math
_____________________________________________

Finding a Circle's Area Without Pi


Date: 02/24/2001 at 22:02:14
From: Anna
Subject: Finding the area of a circle without using pi

I need to find out how to find the area of a circle without using pi. 
I have to explain it and prove the answer.

Please help.


Date: 02/25/2001 at 13:17:55
From: Doctor Roy
Subject: Re: Finding the area of a circle without using pi

Hello,

Thanks for writing to Dr. Math.

There is a way, although it's really more of a cheat. Remember how pi 
is defined. It is the ratio of the circumference of a circle to its 
radius, or:

     pi = C/d

Now the area of a circle is given by the following formula:

     A = pi*r^2

We can combine these two facts to get an expression that does not have 
pi in it. Of course pi will be involved, but it will be hidden in the 
interaction between circumference and diameter.

I hope this helps.

- Doctor Roy, The Math Forum
  http://mathforum.org/dr.math/   
    
Associated Topics:
Middle School Conic Sections/Circles
Middle School Geometry
Middle School Pi

Search the Dr. Math Library:


Find items containing (put spaces between keywords):
 
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

_____________________________________
Math Forum Home || Math Library || Quick Reference || Math Forum Search
_____________________________________

Ask Dr. MathTM
© 1994-2013 The Math Forum
http://mathforum.org/dr.math/