Find the missing side of a right triangle using a² + b² = c², solving for either the hypotenuse or a leg.
Select which side to solve for — hypotenuse or a leg.
Length of leg A (adjacent to the right angle). Must be positive.
Length of leg B — the other leg.
Missing Side
5.0000
The length of the side you asked to solve for, via a² + b² = c².
Computed
Hypotenuse
Which side was computed (A, B, or hypotenuse).
What this means
Applies only to right triangles. Given any two sides, it solves for the third.
For a right triangle, the square of the hypotenuse equals the sum of the squares of the two legs. Use this tool to find any missing side.
Formula
c² = a² + b² ⇒ c = √(a² + b²) | a = √(c² − b²)
Worked examples
FAQ
When is the leg result invalid?
The longer side you enter must be the hypotenuse; if it is not longer than the other side, the calculation cannot resolve.
Does this work for non-right triangles?
No — the Pythagorean theorem applies only to right triangles.
Limitations