CBSE Guess > Papers > Important Questions > Class X > Maths > Mathematics By Mr. Sanjay Kumar

Chapter - 13

Q. 141. From a point P on the ground, the angles of elevation of the top of a 10m tall building and of a helicopter, hovering at Some height over the top of the building are 30⁰ and 60⁰, respectively. Find the height of the helicopter above the ground.

Q. 142. From the top of a cliff 50 m high, the angles of depression of the top and the bottom of a tower are observed to be 30⁰ and 45⁰ respectively. Find the height of the tower.

Q. 143. The angle of elevation of a jet-plane from a point A on the ground is 60⁰. After a flight of 15 seconds, the angle of elevation changes to 30⁰. If the jet plane is flying at a constant height of 1500√3 meters, find the speed of the jet plane.

Q. 144. From the top of a hill, the angles of depression of two consecutive kilometer stones due east are found to be 30⁰ and 45⁰. find the height of the hill.

Q. 145. If the angle of elevation of a cloud from a point h metres above a lake is  and the angle of depression of its reflection in the lake is , prove that the height of the cloud is [ h (tan  + tan  )] / ( tan  – tan ).

Q. 146. An aeroplane at an altitude of 200 meters observes the angles of depression of opposite points on two banks of a river to be 45⁰ and 60⁰. Find the width of the river.

Q. 147. An aero plane when flying at a height of 4000 m from the ground passes vertically above another aero plane at an instant when the angles of elevation of the two aero planes from the same point on the ground are 60º and 45º respectively. Find the vertical distance between the two aero planes at that instant.

Q. 148. The shadow of a tower, standing on level ground, is found to be 45 m longer when Sun’s altitude is 30⁰ than when it was at 60⁰. Find the height of the tower.

Q. 149. From the top of a building 12 m high, the angle of elevation of the top of a tower is found to be 30⁰. From the bottom of the same building, the angle of elevation of the top of the tower is found to be 60⁰. Determine the height of the tower and the distance between the tower and the building.

Q. 150. A man standing on the top of a building 45 m high is looking at two advertising pillars on the same side whose angles of depression are 30⁰ and 60⁰, respectively. What is the distance between the pillars? [Assume the two pillars as two points on the level ground and in the same straight line].