The foot of a ladder of length 3.75 m is 1.4 m away from a vertical wall. How high up the wall will the ladder reach (to the nearest 1 cm)?

Pythagoras Theorem is about a property of all triangles with a right-angle. If a triangle has one angle which is a right-angle (i.e. 90o) then there is a special relationship between the lengths of its three sides. This theorum is named after the Greek mathematician, Pythagoras.