Answer: a) the angle of elevation which plane's make with the runway is [tex]2\textdegree[/tex]
b) it takes 74.58 miles away from the airport must the pilot begin descending.
Step-by-step explanation:
Height of the commercial airline pilot is flying (PQ)= 6.5 miles
Length from which the pilot begins descending from the airport (PR)= 186 miles
We need to find the angle of elevation:
Consider, ΔPQR,
[tex]\sin \theta=\frac{PQ}{PR}\\\\\sin \theta=\frac{6.5}{186}\\\\\sin \theta=0.035\textdegree\\\\\theta=\sin^{-1}(0.035)\\\\\theta=2\textdegree[/tex]
Hence, the angle of elevation which plane's make with the runway is [tex]2\textdegree[/tex]
Now, According to question,
If the plane’s path is to make an angle of 5° with the runway:
Consider, ΔPQS,
[tex]\sin \theta=\frac{PQ}{PS}\\\\\sin \theta=\frac{6.5}{PS}\\\\\sin 5=\frac{6.5}{PS}\\\\PS=74.58[/tex]
Hence, it takes 74.58 miles away from the airport must the pilot begin descending.