Pythagorean Theorem Calculator
Choose which side you want to find and enter the other two.
How this calculator works
In a right triangle, a squared plus b squared equals c squared, where c is the hypotenuse, the side opposite the right angle. Rearranged, a = sqrt(c squared – b squared). The hypotenuse is always the longest side.
Frequently asked questions
What is a Pythagorean triple?
Three whole numbers that satisfy the theorem, such as 3-4-5, 5-12-13 and 8-15-17.
Does it work for any triangle?
No. It only applies to right triangles.
Which side is the hypotenuse?
The one opposite the 90 degree angle, and always the longest.
