9514 1404 393
Answer:
38.6 mi
Explanation:
The law of sines applies.
b/sin(B) = a/sin(A)
a = b(sin(A)/sin(B)) = (30 mi)sin(40°)/sin(30°)
a ≈ 38.6 mi
Airplane b is about 38.6 miles from the airport.
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We have used the usual convention that the side opposite an angle is named using the lower-case letter naming the angle. Here, the angles are named by the airplane designator (A or B).