Jl i oi andIf PR 6.4 cm, then find PT). The angle of elevation of the

1.	Jl i oi andIf PR 6.4 cm, then find PT). The angle of elevation of the top of a building from the foot of a tower is 30 and the angle ofelevation of the top of the tower from the foot of the building is 60° If the tower is 50 m high, thefind the height of the building
Answer» Let AB be the height of the building. BC be the distance between the foots of the building and the tower. Elevation is 30° and 60° from the tower and the building respectively. ATP In right ΔBCD, tan 60° = CD/BC ⇒ √3 = 50/BC ⇒ BC = 50/√3 also, In right ΔABC, tan 30° = AB/BC ⇒ 1/√3 = AB/BC ⇒ AB = 50/3 Thus, the height of the building is 50/3.

Jl i oi andIf PR 6.4 cm, then find PT). The angle of elevation of the top of a building from the foot of a tower is 30 and the angle ofelevation of the top of the tower from the foot of the building is 60° If the tower is 50 m high, thefind the height of the building

Answer»

Let AB be the height of the building.

BC be the distance between the foots of the building and the tower.

Elevation is 30° and 60° from the tower and the building respectively.

ATP

In right ΔBCD,

tan 60° = CD/BC

⇒ √3 = 50/BC

⇒ BC = 50/√3

also, In right ΔABC,

tan 30° = AB/BC

⇒ 1/√3 = AB/BC

⇒ AB = 50/3

Thus, the height of the building is 50/3.