Q. 1. The angle of elevation of a cloud from a point 60 meters above a lake is 
and the angle of depression of the reflection of the cloud in the lake is 
.Find the height of cloud.
Q. 2. From the top of a tower 60 meters high , the angles of depression of the top and bottom of a pole are observed to be 
and 
respectively. Find the height of the pole if the Pole and tower stand on the same plane.
Q. 3. A vertical tower stands on a horizontal plane and is surmounted by a vertical flagstaff of height h. At a point on the plane, the angles of elevation of the bottom and the top of the flagstaff are 
and 
respectively. Prove that the height of the tower is
Q. 4. The angle of elevation of an aeroplane from a point on the ground is 
. After flying for 15 seconds, the elevation changes to 
.If the aeroplane is flying at a height of 2500 meters, find the speed of the aeroplane .
Q. 5. An aeroplane when 3000 m heigh passes vertically above another aeroplane at an instance when their angles of elevation , at the same observation point are 
and 
respectively. How many meters higher is the one than the other.
Q. 6. A round balloon of radius r subtends an angle 
at the eye of the observer while the angle of elevation of its center is 
. Prove that the height of the centre of the balloon is
Q. 7. Two stations due south of leaning tower which leans towards the north are at distance a and b from its foot . If 
,
be the elevations of the top of the tower from these stations , Prove that its inclination 
to the horizontal is given by
