If the height of a tower and the distance of the point of observation from its foot, both are increased by 10%, then the angle of elevation of its top remains unchanged.


Let height of the tower be h and distance of the point from its foot is x.

Let angle of elevation be θ1


…eq. 1

Now, when both(height and distance) are increased by we get

New height = h+10%of h

New distance = x+10% of x

In ∆PQR,

From eq.1 and eq.2, we get θ1 = θ2

Hence, it is true.