Answer:
Option C is correct
Step-by-step explanation:
Given: A plane is descending onto the runway with an angle of depression of 55°. Also, it has 2.8 miles to go before landing.
To find: current altitude of the plane
Solution:
Consider the attached image.
In ΔABC,
[tex]\angle ACB=55^{\circ}[/tex] (Alternate interior angles)
For any angle [tex]\theta[/tex],
[tex]tan \theta[/tex] = side opposite to angle/side adjacent to angle
[tex]\tan C=\frac{AB}{BC}[/tex]
Put [tex]\angle C=55^{\circ}\,,\,BC=2.8\,\,miles[/tex]
[tex]AB=2.8\,\tan 55^{\circ}=3.999\approx 4\,\,miles[/tex]
So, the current altitude of the plane is 4 miles.
