(Q2) A ladder 25 m long reaches a window of building 20 m above the ground. Determine the distance from the foot of the ladder to the building.

Solution :

In ∆ABC, ∠C = 90^o

⇒ AB² = AC² + BC² (by Pythagorean theorem)

⇒ ( )² = ( )² + BC²

BC² = - =

BC = √ ( ) = m

Hence, the foot of the ladder is at a distance of m from the building.