An aeroplane when flying at a height of 4000m from the ground passes vertically below another plane at an instant when the angles of elevation of the two planes from the same point on the ground are 60° and 45° respectively. Find the distance between the two planes at that instant.
We consider tangernt with respect to A.
And with respect to A height =CD and base is AC
So tan A = Height/ base or CD/AC
So its correct!!