Question
Two ships are sailing in the sea on the either side of the lighthouse, the angles of depression of two ships as observed from the top of the lighthouse are 60° and 45° respectively. If the distance between the ships is 200 
Find the height of the lighthouse.
Solution
Let AD be the lighthouse of height h m B and C are the position of the two ships which are on the either side of the road. The angles of depression of the ships from the top of the light house be 60° and 45°, ie., ∠ABD = 60 and ∠ACD = 45°
Let BD = x m and CD = y m.
In right triangle ABD, we have
In right triangle ACD, we have
Adding (i) and (ii), we get
Hence, the height of the light house = 200 m.
