Heights and distances
- From the top of a lighthouse 75 m high, the angle of depression of a ship is 30°. How far is the ship from the foot of the lighthouse? Answer: C. 75√(3) m Answer: (C) 75√(3) m tan 30^° = 75/d , so d = 75√(3) m (about 129.9 m). 1
- From a point on the ground, the angle of elevation of the top of a tower is 30°. On walking 20 m towards the tower, the angle of elevation becomes 60°. What is the height of the tower? Answer: A. 10√(3) m Answer: (A) 10√(3) m Let the nearer point be x m from the foot. h = xtan 60^° = x√(3) and h = (x + 20)tan 30^° = x + 20/... 1