# Pythagorean theorem

- the theorem that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides.

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## Origin of Pythagorean theorem^{}

First recorded in 1905–10

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Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

## Pythagorean theorem

[pĭ-thăg′ə-rē′ən]

- A theorem stating that the square of the length of the hypotenuse of a right triangle is equal to the sum of the squares of the lengths of the other sides. It is mathematically stated as c2 = a2 + b2, where c is the length of the hypotenuse and a and b the lengths of the other two sides.

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The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

## Pythagorean theorem

[(puh-thag-uh-ree-uhn, peye-thag-uh-ree-uhn)]

The theorem in geometry that, in a triangle with one right angle, usually called a right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other two sides.

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## Note

The theorem is often expressed a2 + b2 = c2.

## Note

The simplest whole number expression of this theorem is called the 3, 4, 5 triangle. In a right triangle, if one side measures three units, and the second side measures four units, the hypotenuse must measure five units because 32 + 42 = 52; that is, 9 + 16 = 25.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.