Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 7 - No. 32)
If you are given the lengths of the two legs of a right triangle, how do you find the hypotenuse?
Add the lengths together.
Subtract the smaller length from the larger length.
Use the Pythagorean Theorem.
Multiply the lengths together.
Explication
The Pythagorean Theorem (a^2 + b^2 = c^2) is used to find the hypotenuse when you know the lengths of the two legs.