From an aero plane flying, vertically above a horizontal road, the angles of depression of two consecutive stones at a distance of km on the same side of the aeroplane are observed to be and , respectively.
The height (in km) at which the aero plane is flying, is:
The explanation for the correct option:
Step: 1 Find the height of the triangle using trigonometric identities:
Step: 2 Find the height of the triangle using trigonometric identities:
Step: 3 Calculate the value of :
From(i) and (ii) we get
Now, putting the value of in any equation of , we get:
Hence, the height at which aero plane is flying is km.
Hence, Option(B) is the correct answer.