From an airplane at an altitude of 1200m the angle of depression to a rock on the ground measures 28. Find the distance from the plane to the rock

Given that the plane is at altitude of 1200m and the angle of depression is 28°, to calculate the distance between the the plane and the rock we assume that we a have right triangle whereby the distance of the plane form the ground is the height, the distance from plane to the rock is the hypotenuse and the remaining distance is the base:

thus

sin θ=opposite/hypotenuse

θ=28°

opposite=1200m

hypotenuse=h

thus

sin 28=1200/h

h=1200/sin 28

h=2556.065 m