Answer:
The horizontal distance from the plane to the control tower is 61630.7 ft.
Explanation:
Here we have that
Height of flight of plane = 13,100 ft = Opposite side of angle of elevation
Angle of depression from the plane to the control tower = 12°
Therefore, the control tower can be sighted on a straight (hypotenuse) line from the plane with an angle of depression of 12°
Angle of depression from the plane to the control tower = Angle of elevation from the control tower to the plane = 12°
Horizontal distance from the plane to the control tower = Adjacent side of the hypotenuse of the right triangle = (Opposite side of angle of elevation) ÷ (Tangent of angle of elevation)
∴ Horizontal distance from the plane to the control tower = 13,100/(tan(12°)
Horizontal distance from the plane to the control tower = 61630.7 ft. to the nearest tenth of a foot.