# Some Applications of Trigonometry – Class X – Part 4 | Exercise 9.1 Q9-10 Solved

### Watch the fourth video session on “Some Applications of Trigonometry” for Class Xth – concepts and solved questions

Some Applications of Trigonometry – NCERT Class X – Part 4

1. Astronomers used Trigonometry to calculate distances from the Earth to the other planets and starts.

2. It is also used to construct in geography to construct maps and in navigation.

3. Line connecting the observer’s eye to the position of the object being viewed is called line of sight.

4.Horizontal level is the line that we get when we look absolutely straight (neither up or down).

5. Angle formed between line of site and horizontal level is called the angle of elevation.

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NCERT Exercise 9.1 Q9 – 10 Solved

9. The angle of elevation of the top of a building from the foot of the tower is 30° and the angle of elevation of the top of the tower from the foot of the building is 60°. If the tower
is 50 m high, find the height of the building.

10. Two poles of equal heights are standing opposite each other on either side of the road, which is 80 m wide. From a point between them on the road, the angles of elevation of
the top of the poles are 60° and 30°, respectively. Find the height of the poles and the distances of the point from the poles.

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