Pythagorean Theorem Calculator
Find a missing side of a right triangle from the other two.
Result
Enter values and press Calculate to see the result.
Formula
In a right triangle, the square of the hypotenuse equals the sum of the squares of the legs.
How to use this calculator
- Choose what to find, enter the two known sides and press Calculate.
- The hypotenuse is the longest side, opposite the right angle.
Worked example
Legs 3 and 4
c² = 3² + 4² = 9 + 16 = 25.
c = √25 = 5.
Frequently asked questions
Why might I get a square root in the answer?
Most side lengths are irrational, like √2. Sumzo keeps them exact and shows the decimal too.
Does it work for any triangle?
No — only right triangles (one 90° angle).