Answer:
Angle of depression = 3.37°
Step-by-step explanation:
We are told that A plane flies at an altitude of 3.5 kilometers and then starts to descend when it is 60
kilometers from the runway.
I've attached an image of a triangle depicting this question.
From the triangle, we can find the angle of depression θ from trigonometric ratio since it's a right angle triangle.
Thus;
3.5/60 = tan θ
tan θ = 0.0583
θ = tan^(-1) 0.0583
θ = 3.37°