Overview
What Is the Pythagorean Theorem?
The Pythagorean theorem states that in a right triangle, a² + b² = c², where c is the hypotenuse (longest side).
Find the missing side of a right triangle instantly.
a² + b² = c²
The Pythagorean theorem states that in a right triangle, a² + b² = c², where c is the hypotenuse (longest side).
Useful for finding a missing side length in any right triangle.
Input any two of the three sides (a, b, or c).
The calculator solves for the missing value.
The missing side updates automatically.
a² + b² = c², where c is the hypotenuse and a, b are the other two sides.
The longest side, always opposite the right angle.
No, the Pythagorean theorem only applies to right triangles (with one 90-degree angle).
You could verify whether the triangle is actually a right triangle by checking if a²+b²=c² holds true.
Sets of three whole numbers satisfying the theorem exactly, like 3-4-5 or 5-12-13.
Yes, decimal measurements are fully supported.
Yes, checking for square corners (using the 3-4-5 rule, for example) is a common practical application.
No, calculations happen entirely in your browser.
Yes, entering the two shorter sides (a and b) lets you calculate c (hypotenuse) directly.
Yes, completely free with no sign-up required.