Question

The hypotenuse of a right triangle is 50mm long one leg of the right triangle is 30 mm long what is the length of the other leg

Answer 1

The triangle you are describing is the common 3,4,5 triangle. So the side lengths are 30, 40, and the hypotenuse is 50. This comes from Pythagorean theorem $a^{2} + b^{2} =c ^{2}$