Answer:
11.3°
Step-by-step explanation:
Refer the attached figure .
Height of building i.e. AB = 160 feet.
A helicopter takes off from the ground 800 feet from the base of a building i.e. BC = 800 ft.
We are required to find what angle did the helicopter take off from i.e. ∠ACB
We will use trigonometric ratio .
[tex]tan\theta = \frac{Perpendicular}{Base}[/tex]
[tex]tan\theta = \frac{AB}{BC}[/tex]
[tex]tan\theta = \frac{160}{800}[/tex]
[tex]tan\theta = \frac{1}{5}[/tex]
[tex]tan\theta = 0.2[/tex]
[tex]\theta =tan^{-1} 0.2[/tex]
[tex]\theta =11.3^{\circ}[/tex]
Thus the angle at which the helicopter take off from is 11.3°
