Pythagorean Theorem Calculator
Find the missing side of a right triangle — hypotenuse or either leg — using the Pythagorean theorem.
Example values are shown — change any of them and the answer updates live.
a
b
Hypotenuse
5
a=3 · b=4 · c=5
With the given two sides, the missing side and area are shown on the triangle.
Leg a3
Leg b4
Hypotenuse5
Area6
How the side is found
Step 1 · Square the known sides
c² = a² + b²
9 + 16
25
Step 2 · Take the square root
√
√
5
Exact arithmetic — computed instantly in your browser.