An airplane leaves an airport and flies due west 120 miles and then 150 miles in the direction s 39.17°w. how far is the plane from the airport (round to the nearest mile)?

Mark the airport with A, the current position of the plane P, and the turning point B.

m(ABP)=39.17°+90°=129.17°

Given 2 sides and the measure of the angle between them, we can find the third side by the cosine law:







(miles)

remark : cos 129.17° can be found by searching in google : cosine calculator, or using other software.

The correct answer is -20y