1. Presented by RAMA KRISHNA RAO AD KV, PICKET

3. QNo. From a point 100m above a lake, the angle of elevation of a stationary cloud is 30 0 and the angle of depression of reflection of the cloud in the lake is 60 0. Find the height of the cloud from the lake. 100m 30 0 60 0 h A B C D E F Sol: Let BC – surface of the lake A – point of observation AB = 100m ED = h (height of the cloud) ---------(i) In rt. ∆EDA

4. Hence, the height of the cloud from the surface of the lake = h + DC = 100 + 100 = 200m 100m 30 0 60 0 h A B C D E F In rt. ∆FDA

5. A 1.2 m tall girl spots a balloon moving with the wind in a horizontal line at a height of 88.2 m from the ground. The angle of elevation of the balloon from the eyes of the girl at any instant is 60°. After some time, the angle of elevation reduces to 30°.Find the distance travelled by the balloon during the interval. Sol: Que: 1.2 m 88.2 m 60 0 30 0 E B C D A F

6. 1.2 m 88.2 m 60 0 30 0 E B C D A F Let AC = 88.2m (height of the balloon from the ground) BC = 1.2m (height of the girl. AB = AC – BC = 88.2 – 1.2 = 87m In rt ∆ ABDIn rt ∆ EFD BF = 100.34 m The distance travelled by the balloon during the interval is 100.34m

8. A man on deck of ship is 10m above water level. He observes that the angle of elevation of top of a hill is 60 0 and angle of depression of base of hill is 30 0. Calculate the distance of hill from ship and height of the hill. From an aeroplane vertically above a straight horizontal plane, the angles of depression of two consecutive kilometers stones on opposite sides of the aeroplane are found to be α and β. Show that height of the aeroplane is. Que 1: Que 2: