Q. 165.0( 4 Votes )

# It is found that on walking x meters towards a chimney in a horizontal line through its base, the elevation of its top changes from 30° to 60°. The height of the chimney is

A.

B.

C.

D.

Answer :

Here AB is the chimney of height h

By walking x meters toward chimney the angle of elevation changes from 30° to 60°

In Δ ABH

tan 60° =

h = √3 y

= y …………….1

In Δ ABG

tan 30° =

=

√3 h = x+y

√3 h - = x (from 1)

= x

h =

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