Question

The angle of elevation of top of a tower from certain point is 30° if the Bessemer mines 20m towards the tower , the angle elevation of the top increases by 15° find the height of the tower.
plz urgent.

Answer 1

Let the height of tower is h
and x is the distance from foot of tower and first point of bessemer
tan30°=P/B=h/x
1/√3=h/x
x=√3 ×h...(1)

tan 45°=P/B =h/x-20
1=h/x-20
x-20=h
x-h=20
from eq.(1)
(√3×h)-h=20
h(√3-1)=20
h=20/√3-1
height of tower=20/√3-1