Mathematics
The angle of elevation of a stationary cloud from a point 25 m above a lake is 30° and the angle of depression of its reflection in the lake is 60°. What is the height of the cloud above the lake-level?
Related Questions
From a boat, 200 m away from a vertical cliff, the angles of elevation of the top and the foot of a vertical pillar at the edge of the cliff are 36° and 34° respectively. Find:
(i) the height of the cliff, and
(ii) the height of the pillar.
A man on the top of a vertical observation tower observes a car moving at a uniform speed coming directly towards it. If it takes 10 minutes for the angle of depression to change from 30° to 45°, how soon after this will the car reach the observation tower? Give your answer to the nearest second.
A tower subtends an angle α on the same level as the foot of the tower and at a second point h metres above the first, the depression of the foot of the tower is β. Show that the height of the tower is h tan α cot β.
The angle of elevation from a point P of the top of a tower QR, 50 m high, is 60° and that of the tower PT from a point Q is 30°. Find the height of the tower PT, correct to the nearest metre.