Please find the attached diagram for a better understanding of the solution given here.
B is the base of the Vertical Drop. Thus, AB=32 feet.
AC is the water slide and thus the length of AC is 350 feet.
We need to find the angle of depression which in this case is
.
As can be seen from the diagram,
and
are alternate interior angles where the water slide, AC, is the transversal and thus they will be equal.
therefore,

Let us make use of the
to find
using the Sine trigonometric ratio.
Thus,



Thus Angle of Depression is
, which the required answer.