Question

A 13 m ladder leans against a vertical wall. The foot of the ladder is 5 m from the wall. How high up the wall does the ladder reach?

Solution

1. The wall, the ground, and the ladder form a right triangle, with the ladder as the hypotenuse (13 m).
2. By Pythagoras theorem, height^2 = 13^2 - 5^2 = 169 - 25 = 144.
3. Height = √144 = 12 m.
4. The ladder reaches 12 m up the wall.