(Q3) A TV tower stands vertically on the side of a road. From a point on the other side directly opposite to the tower, the angle of elevation of the top of tower is 60o. From another point 10 m away from this point, on the line joining this point to the foot of the tower, the angle of elevation of the top of the tower is 30o. Find the height of the tower and the width of the road.

Answer :

603010 mxroadhtower

Let the height of the tower = h mts say

Width of the road be = x m.

Distance between two points of observation = 10 cm.

Angles of elevation from the two points = 60o and 30o.

tan 60° =
h
x
=
h
x

h = √ x .....(1)

Also tan 30o =
h
+ x
1
=
h
+ x
h =
+ x
.....(2)

From equations (1) and (2) h

h = √ x =
+ x
∴ √ x =
+ x

× √ x = + x

x - x =

x =

x = m

∴ Width of the road = m

Now Height of the tower = √ x = m.