Pythagorean Theorem

Definition

For any right triangle, the square of the hypotenuse equals the sum of squares of the other two sides: a² + b² = c². Named for the Greek mathematician Pythagoras, the theorem has over 370 known proofs and is the most-used geometric identity in construction, navigation, and computer graphics. Common Pythagorean triples, integer-sided right triangles, include 3-4-5, 5-12-13, 8-15-17, and 7-24-25. Carpenters use the 3-4-5 rule to check that framing corners are square without a protractor.