A ladder 20 m long is leaning against a vertical wall. It makes an angle of 30° with the ground. How high on the wall does the ladder reach?

The shadow of a tower when the angle of elevation of the sun is 45 °, is found to be 10 m longer that when it was 60 °. The height of the tower is 

From a point P on a level ground, the angle of elevation of the top tower is 30°. If the tower is 100 meter high, the distance of point P from the foot of the tower is:

A kite is flying in the sky. The length of string between a point on the ground and kite is 420 m. The angle of elevation of string with the ground is 30^o. Assuming that there is no slack in the string, then what is the height (in metres) of the kite?

A telegraph post is bent at a point above the ground. Its top just touches the ground at a distance of 8√3 m from its feet and makes an angle of 30 ° with the horizontal. The height (in metre) of the post is 

An Aeroplan is flying horizontally at a height of 1.8 km above the ground. The angle of elevation of plane from point X is 60° and after 20 seconds, its angle of elevation from X becomes 30°, If point X is on ground, then what is the speed (in km / hr.) of Aeroplan? 

A ladder rests against a wall at a height of 10 meters. If the ladder makes 30° along the ground. Find the distance from the wall of the foot of the ladder.

If the angle of elevation of the sun changes from 30^o to 45^o then length of the shadow of a pillar decreases by 20 meters. The height of the pillar is: