Q. 74.3( 274 Votes )
From a point on the ground, the angles of elevation of the bottom and the top of a transmission tower fixed at the top of a 20 m high building are 45° and 60° respectively. Find the height of the tower.
In a right-angled triangle, we know,
Since the building is vertical.
∠QPO = 90°
tan 45° =
OP = 20 -------(1)
Now in ∆OPR
tan 60° =
20√3 = h+20
h = 20√3-20
h = 20(√3-1) m.
Therefore the height of transmission tower is 20(√3-1) m.
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