Question
From the top of a 7 m high building, the angle of elevation of the top of a cable tower is 60° and the angle of depression of its foot is 45°. Determine the height of the tower
Solution
Let AC be the building whose height is 7 m and BE be the cable tower.
It is given that the angle of elevation of the top E of the cable tower from C and the angle of depression of its foot from C be 60° and 45° respectively.
i.e., ∠DCE = 60° and ∠BCD = 45°.
Also, AC = BD = 7 m.
Let DE = h m
In right triangle DCE, we have
Now, in right triangle BCD, we have
Comparing (i) and (ii), we get
Hence, Total height of the cable lower (BE)
