9. The angle of elevation of the top of a building from the foot of the tower is 30° and the angle of elevation of the top of the tower from the foot of the building is 60°. If the tower is 50 m high, find the height of the building.
It is given that, the height of the tower (AB) is 50 m. and
Let the height of the building be m
According to question,
In triangle PBQ,
.......................(i)
In triangle ABQ,
.........................(ii)
On equating the eq(i) and (ii) we get,
therefore, = 50/3 = 16.66 m = height of the building.