Enter any two sides of a right triangle (two legs, or one leg and the hypotenuse) to instantly find the missing side using the Pythagorean theorem.
This tool applies the Pythagorean theorem to find a missing side length of a right triangle when the other two sides are known.
The theorem states a squared plus b squared equals c squared, where c is the hypotenuse, the longest side opposite the right angle.
Enter any two of the three sides and leave the unknown one blank, then click Calculate to find the missing value.
Example: If a equals 6 and b equals 8, then c equals the square root of 36 plus 64, which is 10.
Who discovered this theorem. It is attributed to the ancient Greek mathematician Pythagoras, though it was known earlier in other cultures.
Does it work for any triangle. No, it only applies to right triangles, where one angle is exactly 90 degrees.