(Q4) A 1.5 m tall boy is looking at the top of a temple which is 30 metre in height from a point at certain distance. The angle of elevation from his eye to the top of the crown of the temple increases from 30^o to 60^o as he walks towards the temple. Find the distance he walked towards the temple.

Solution :

Height of the temple = 30 m

Height of the man = 1.5 m

Initial distance between the man and temple = d m. say

Let the distance walked = x m.

From the figure

∴ d = 28.5 × √3 m......(1)

√ (d - x) =

√( × √ - x) =

× - √ x =

√ x = × -

√ x = × =

=

= m.

∴ Distance walked = m.