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Mathematics

Pythagorean Theorem

Pythagorean Theorem — a² + b² = c²

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Variable Legend

a= leg (short side)b= leg (other short side)c= hypotenuse (longest side, opposite 90°)

Find hypotenuse c

Given both legs a and b.

Find leg a or b

Given the hypotenuse and one leg.

Find a
Find b

Pythagorean triples

Integer right triangles (whole number sides).

3-4-5
5-12-13
8-15-17
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Pro Tip

When two sides have a ratio close to 3:4, check if the third side is 5× the GCD. This instantly confirms a 3-4-5 family triple.

Difficulty:Intermediate

Did you know?

There are over 370 known proofs of the Pythagorean theorem — more than any other theorem in mathematics. One was written by US President James Garfield in 1876.

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Reviewed May 2026
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