A ladder 13 m long, reaches a window 12 m above the ground. Find the distance of the foot of the ladder from the base of the wall.

We can visualize this scenario as a right triangle ABC. We need to find the base of the right triangle BC formed.

Length of the ladder, AC = 13 m

AB = 12 m

In △ABC,

AC² = BC² + AB²      (Pythagoras Theorem)

⇒ (13)² = BC² + (12)²

⇒ BC² = 169 − 144

⇒ BC² = 25

⇒ BC = 5 m

Therefore, the distance of the foot of the ladder from the base of the wall is 5 m.