How would you work out the length of an hypotenuse, if the length of the opposite side is 3 cm and the length of the opposite side is 4 cm?

You would use Pythagoras theorem, which states, a^2 + b^2 = c^2. Where a is the opposite side to the angle, b is the side adjacent to the angle and c is the hypotenuse.

So if a = 3 cm, and b = 4 cm, c^2 would equal: 3^2 + 4 ^2 = 9 + 16 = 25. If c^2 = 25, then c = 5. Therefore the length of the hypotenuse is 5cm.