Question

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

Answer 1

Let AC be the ladder and A be the position of the window.
Then, AC = 25m, AB = 20m
Using Pythagoras theorem,
AC² = AB² + BC²
⇒ (25m)² = (20m)² + BC²
⇒ BC² = 625m² - 400m²
BC² = 225m²
BC² = (15m)²
⇒ BC = 15m
Thus, the distance of the foot of the ladder from the building is 15m.