(Q9) Two poles of equal heights are standing opposite to each other on either side of the road, which is 120 feet wide. From a point between them on the road, the angles of elevation of the top of the poles are 60o and 30o respectively. Find the height of the poles and the distances of the point from the poles.

Solution :

hh3060x(120-x)120 ft

Width of the road = 120 f.

Angle of elevation of the top of the 1st tower = 60°.

Angle of elevation of the top of the 2 tower = 30°.

Let the distance of the point from the 1st pole = x.

Then the distance of the point from the 2nd pole = 120 - x.

and height of each pole = h say.

From the figure

tan 60° =
h
x
=
h
x

h = √ x ....(1)

Also tan 30°=
h
- x
1
=
h
- x
h =
- x
....(2)

from (1) and (2)

x =
- x

.√ x = - x

x = - x

x + x =

x =

x = ft

Now h = √ x = √× = 1.732 x = .960 feet

∴ Distances of the poles = ft. and 120 - fts = ft.

Height of each pole = .96 ft.