Pythagorean Theorem Calculator
Enter any two sides of a right triangle to find the third. a² + b² = c²
Enter exactly two values. Leave the unknown side blank.
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Frequently Asked Questions
What is the Pythagorean theorem?
a² + b² = c² for right triangles. The hypotenuse squared equals the sum of the other two sides squared.
What are Pythagorean triples?
Whole-number sets that satisfy the theorem: 3-4-5, 5-12-13, 8-15-17, 7-24-25. Multiples work too.
Does this work for non-right triangles?
No. Use the Law of Cosines (c² = a² + b² − 2ab·cos C) for other triangle types.