A man standing on the deck of the ship which is 20 m above the sea-level, observes the angle of elevation of a bird as 30 degree and the angle of depression of its reflection in the sea as 60 degree. Find the height of the bird.

There is a small island in between a river 100 metres wide. A tall tree stands on the island. P and Q are points directly opposite to each other on the two banks and in the line with the tree. If the angles of elevation of the top of the tree from P and Q are 300 and 450 respectively, find the height of the tree.

A man on the deck of a ship is 16 m above the water level. He observes that the angle of elevation of the top of a cliff is 450 and the angle of depression of the base is 300. Calculate the distance of the cliff from the ship and the height of the cliff. Solution:

An aeroplane is flying horizontally 1 km above the ground is observed at an elevation of 600. After 10 seconds, its elevation is observed to be 300. Find the speed of the aeroplane in km/hr.

In the adjoining figure, the angle of elevation of the top P of a vertical tower from a point X is 60 degree; at a point Y, 40 m vertically above X, the angle of elevation is 450. Find (i) the height of the tower PQ (ii) the distance XQ (Give your answer to the nearest metre)

A boy 1.54 m tall can just see the sun over a wall 3.64 m high which is 2.1 m away from him. Find the angle of elevation of the sun.

In the adjoining figure, the shadow of a vertical tower on the level ground increases by 10 m, when the altitude of the sun changes from 450 to 300. Find the height of the tower and give your answer, correct to 1/10 of a metre.