If the angle of elevation of a balloon from two consecutive kilometer-stones along a road are 30° and 60° respectively, then the height of the balloon above the ground will be 

The angle of elevation of ladder leaning against a house is 60° and the foot of the ladder is 6.5 meters from the house. The length of the ladder 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 kite is flying at a height of 50m. If the length of string is 100m then the inclination of string to the horizontal ground in degree measures is:

The angle of elevation of the top of a tower from two points A and B lying on the horizontal through the foot of the tower are 159 and 30° respectively. If A and B are on the same side of the tower and AB = 48 meter, then the height of the tower is; 

A pilot in an aeroplane at an altitude of 200 m observes two points lying on either side of a river. If the angles of depression of the two points be 45 ° and 60 °, then the width of the river is 

The angle of elevation of the foot of a house from the top of a tower is twice the angle made with the top of this house. If the height of the tower is 75 meters. And the elevation angle of the foot of the house from the top of the tower is 60 degrees. So what is the height of the house?

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