Answer the following questions, using trigonometry rules.
Class 10th CBSE, Rd Sharma, some applications of trigonometry
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14. The angle of elevation of a tower from a point on the same level as the foot of the tower is 30°. On advancing 150 meters towards the foot of the tower, the angle of elevation of the tower becomes 60°. Show that the height of the tower is 129.9 metres.
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Solution:
Given,
The angle of elevation of top tower from first point D, α = 30°
On advancing through D to C by 150 m, then CD = 150 m
Angle of elevation of top of the tower from second point C, β = 60°
Let height of tower AB = H m
Representing the above data in form of figure then it form a figure as shown with ∠B = 90°
Substituting (b) in (a), we have
H = 129.9
Therefore, the height of the tower = 129.9 m