The Math Forum

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

Pythagorean Theorem

Date: 19 Jan 1995 13:13:05 -0500
From: Margaret Gallegos
Subject: Question

What is the Pythagorean Theorem?

Date: 19 Jan 1995 14:09:42 -0500
From: Dr. Math Margaret Patterson
Subject: Re: Question

Hi there.

Thanks for writing to us.  The Pythagorean Theorem has to do with the
lengths of the sides of a right triangle.  A right triangle is any triangle
which has one right angle (an angle of 90 degrees) - like this:  |__

If the sides next to the right angle are of lengths a and b, and the third
side is of length c, then (a*a) + (b*b) = (c*c).  When people say this,
they say, "a squared plus b squared equals c squared because when you
multiply a number by itself like a*a, you call it a squared.  This can be
written as a^2.

        | \              2    2    2
      a |  \ c          a  + b  = c
        |   \

Some numbers that work in this equation are, 3,4, and 5, and
                                             5, 12, and 13

So if you are told that you have a right triangle whose sides are 3 and 4,
like this:

        | \             Then you can use this theorem to find out what the
      3 |  \ c          third side is.
        |   \           3*3 + 4*4 = 9 + 16 = 25 = 5*5, so c=5

Let us know if you have any other questions.

-Margaret, Doctor on call.
Associated Topics:
Middle School Triangles and Other Polygons

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- The Math Forum at NCTM. All rights reserved.