Question

16. BC is a tower, B is its base. A is a point on a horizontal line passing through B, the
angle of elevetion of C from A is 60° From another point Don AB, the angle of
elevation is found to be 30°, then BD=​

Answer 1

Answer:

h=asinθ=2asinθcosθ⟶1

In △PBC, by sine rule

sin(π−3θ)

a

=

sinθ

b

∴

b

a

=

sinθ

3sinθ−4sin

3

θ

∴sin

2

θ=

4b

3b−a

&cos

2

θ=

4b

a+b

Putting in equation 1

h=

2b

a

(a+b)(3b−a)