A 2 m tall boy is 30 m away from a tower. The angle of elevation of the top of the tower from his eye is 45°. What is the height of the tower?
A 2 m tall boy is 30 m away from a tower. The angle of elevation of the top of the tower from his eye is 45°. What is the height of the tower?
Solution
The angle of elevation is measured from the boy's eye, not from the ground. The boy's eyes are at 2 m height.
Let h be the height of the tower above the boy's eye level.
The horizontal distance from the boy to the tower is 30 m, and the angle of elevation is 45°.
Using the tangent ratio:
Since :
m
The total height of the tower is the height above eye level plus the boy's eye height:
Total height
Total height
Total height m
Therefore, the height of the tower is 32 m.
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