Q. 274.2( 13 Votes )

A T.V. tower stands vertically on a bank of a river. From a point on the other bank directly opposite the tower, the angle of elevation of the top of the tower is 60°. From a point 20 m away this point on the same bank, the angle of elevation of the top of the tower is 30°. Find the height of the tower and the width of the river.

Answer :

Let BC be the height of the T.V tower and AB be the width of the river.

In ∆ABC,

tan 60° =

√3 = ------(1)

In ∆ABC,

tan 30° =

tan 30° =


√3h = 20+ ---------(2)

On substituting value of h in eqn.(2)

√3× √3 = 20+




On substituting value of in eqn. (1)

h = √3

h = 10√3 m.

Therefore height of T.V tower is 10√3 m. and width of river is 10 m.

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