Answer:
968.45 ft
Step-by-step explanation:
You want the horizontal distance from an observer 872 feet high to a ship at an angle of depression of 42°.
The tangent relation is ...
Tan = Opposite/Adjacent
In this geometry, the vertical height of the building is opposite the angle of depression. The side adjacent to the angle is the distance to the ship. This means ...
tan(42°) = (872 ft)/d
d = (872 ft)/tan(42°) ≈ 968.45 ft
The distance out to the ship is about 968.45 ft.