Pythagorean Theorem Calculator
Find a missing side of a right triangle.
Right triangle: legs a and b, hypotenuse c. Enter any two sides.
Result
c = 5
- Hypotenuse c = √(a² + b²).
- c = √(3² + 4²) = √(9 + 16) = √25 = 5.
Formula
a² + b² = c² (c is the hypotenuse)
How it works
Leave the unknown side blank. Legs are a and b; c is across from the right angle.
Common wrong answer
Using a leg as the hypotenuse, or entering all three sides.