Given data:
The given angle of depression is θ= 78°.
The base length is b=20 feet.
The expression for tan(78°) is,
[tex]\begin{gathered} \tan (78^{\circ})=\frac{h}{b} \\ \tan (78^{\circ})=\frac{h}{20\text{ ft}} \\ h=94.09\text{ ft} \\ \approx94.1\text{ ft} \end{gathered}[/tex]Thus, the vertical height is 94.1 ft.
