Question

A pilot can see the runway she is about to land on directly ahead. when looking at each end of the runway the angles of depression are 45 degrees and 42 degrees. if the airplane is 1500 ft off the ground, how long is the runway?

Answer 1

We will use trigonometry:
tan 45° = 1500 / x
1 = 1500 / x
x = 1500 ft
tan 42° = 1500 / y
0.9 = 1500 / y
y = 1500 : 0.9
y = 1666.67 ft
L = y - x ( where L is the length of the runway )
L = 1666.67 - 1500 = 166.67 ft.