Pythagorean theorem calculator

Enter any two sides of a right triangle. The third side comes from a² + b² = c².

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How it’s worked out

a² + b² = c²

Questions people ask

What does the Pythagorean theorem say?

In a right triangle, the square on the hypotenuse (the side opposite the right angle) equals the sum of the squares on the other two sides: a² + b² = c².

What are Pythagorean triples?

Whole-number sides that fit exactly, like 3-4-5, 5-12-13, 8-15-17 and 7-24-25. Builders use 3-4-5 to check a corner is square.