Pythagorean Theorem Solver

Solve right triangle problems using a² + b² = c². Free online Pythagorean theorem calculator.

The Pythagorean Theorem Solver finds the missing side of any right triangle using a² + b² = c². Enter any two sides to find the third. This fundamental geometry tool is essential for construction, navigation, distance calculations, and countless applications where right triangles appear. Works for both finding the hypotenuse and finding a leg.

Common use cases

  • Construction diagonal measurements
  • Ladder safety calculations
  • Screen size from width and height
  • Navigation distance finding
  • Stair building calculations

How to use

  1. Enter two known sides of the right triangle
  2. Specify which is the hypotenuse (longest side)
  3. Click solve for the missing side
  4. View the step-by-step calculation
  5. Verify with the theorem equation

FAQ

What is the Pythagorean theorem?

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

How do I find the hypotenuse?

c = √(a² + b²). For legs 3 and 4: c = √(9+16) = √25 = 5.

How do I find a leg?

a = √(c² - b²). Given hypotenuse 5 and leg 4: a = √(25-16) = √9 = 3.

Does this work for non-right triangles?

No, use the Law of Cosines for non-right triangles: c² = a² + b² - 2ab·cos(C).