Pythagorean Theorem Calculator

How it works

1. 1Choose whether to find the hypotenuse or a missing leg.
2. 2For the hypotenuse, c = √(a² + b²).
3. 3For a leg, leg = √(c² − a²), where c is the hypotenuse.

Use cases

• Find the diagonal of a rectangle or screen.
• Check whether three lengths form a right triangle.
• Solve Pythagorean theorem homework.

Frequently asked questions

What is the Pythagorean theorem?

For a right triangle, a² + b² = c², where c is the hypotenuse (the side opposite the right angle).

How do I find a missing leg?

Rearrange to leg = √(c² − a²). The hypotenuse c must be longer than the known leg.

Does it only work for right triangles?

Yes. The relationship a² + b² = c² holds only when the triangle has a 90° angle.