Answer
The angle of depression is $37.6^{\circ}$
Work Step by Step
We can use the height $h$ and the horizontal distance $d$ to find the angle of depression:
$tan~\theta = \frac{h}{d}$
$\theta = tan^{-1}(\frac{h}{d})$
$\theta = tan^{-1}(\frac{39.82~ft}{51.74~ft})$
$\theta = 37.6^{\circ}$
The angle of depression is $37.6^{\circ}$