The angle of elevation of a ladder leaning against a wall is 60° and the foot of the ladder is 8.5 m away from the wall. The length of the ladder is-

Question: The angle of elevation of a ladder leaning against a wall is 60° and the foot of the ladder is 8.5 m away from the wall. The length of the ladder is-Solution:Let AB be the wall and BC be the ladder.Then, ∠ACB = 60° and AC = 8.5m We know, ⇒ cos∠ACB = AC/BC ⇒ cos60° = AC/BC ⇒ AC/BC = 1/2⇒ BC = 2AC⇒ BC = 2 × 8.5∴ BC = 17 m∴ The length of the ladder is 17 m