Perimeter of an Oval

Date: 04/08/99 at 11:11:08
From: Mrs.Suprin's Class
Subject: The name for the perimeter of an oval

We wanted to know what the name for the perimeter of an oval is. We 
lookeed in a high school geometry book and found no answer. Please 
help us if you can.

Thanks,
Mrs. Suprin's Fifth Grade Class

Date: 04/08/99 at 12:40:14
From: Doctor Peterson
Subject: Re: The name for the perimeter of an oval

Hi, Class!

The shape you are talking about is probably an ellipse, which looks 
like an elongated circle:

                  *****************
            ******                 ******
         ***                             ***
      ***                                   ***
     *                                         *
    *                                           *
    *                                           *
     *                                         *
      ***                                   ***
         ***                             ***
            ******                 ******
                  *****************

If you just want the name of this shape, "ellipse" is the answer.

If you really mean a name for the perimeter, that is, the length of 
the curve, then not only can't I give you a name for it, I can't even 
tell you how to calculate it! This is one of those problems that 
mathematicians have found can't be solved using normal things like 
addition and multiplication, so they just defined new things called 
elliptic integrals. On our FAQ page we give only an approximation:

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

There's another formula here:

   Formula for the Circumference of an Ellipse
   http://mathforum.org/library/drmath/view/54847.html   

If you want to learn more about ellipses, search the Dr. Math 
archives for the words "ellipse" or "conic section". Have fun!

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/