Question

A ladder is placed in such a way that its foot is at a distance of 15 m from a wall and its top reaches a window 20 m above the ground. Find the length of the ladder.

Answer 1

Height of window AC = 20 m

Let length of ladder AB = x m

Distance between the foot of the ladder and the building (BC) = 15 m

In the figure:

By Pythagoras Theorem:

AB² = AC² + BC²

x² = 20² + 15²

= 400 + 225

= 625

or x = 25

Length of ladder is 25 m