# CBSE Class 10-Mathematics: Chapter –9 Some Applications of Trigonometry Part 17

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**Question 5:**

A girl who is tall, spots a balloon moving with the wind in a horizontal line at a height of from the ground. The angle of elevation of the balloon from the eye of the girl at any instant is . After some time, the angle of elevation reduces to . Find the distance travelled by the balloon during the interval.

**Answer:**

In right ,

In right

**Question 6:**

From the top of a tower high, the angles of depression of two cars on a road at the same level as the base of the tower and on same side of it are , where . Find the distance between the two cars.

**Answer:**

In right

In right

## 4 Mark Questions

**Question 1:**

The angle of elevation of the top of a building from the foot of the tower is and the angle of elevation of the top of the tower from the foot of the building is . If the tower is 50 m high, find the height of the building.

**Answer:**

Let the height of the building be m.

In right triangle ABQ,

From eq. (i) and (ii),