From HomoExcelsior

1. The theorem that the sum of the squares of the lengths of the sides of a right triangle is equal to the square of the length of the hypotenuse.

Mathematically, A2 + B2 = C2, where C is the length of the side opposite the right angle (the hypotenuse.) Eg. A=3, B=4, C=5 leads to 32 + 42 = 52 leads to 9+16=25.

See also: 3-4-5 triangle, 345 triangle, Pythagorus

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