Solve the problem.
-An airplane travels at $120 \mathrm {~km} / \mathrm { h }$ for $5 \mathrm { hr }$ in a direction of $312 ^ { \circ }$ from Greenville. At the end of this time, how far west of Greenville is the plane (to the nearest kilometer)?
A) $540 \mathrm {~km}$
B) $807 \mathrm {~km}$
C) $446 \mathrm {~km}$
D) $401 \mathrm {~km}$

Question

Quizplus · Accepted Answer

The westward component of the plane's travel can be calculated using the cosine of the angle from the north. The angle west of north is $360^\circ - 312^\circ = 48^\circ$. The westward distance is $120 \times 5 \times \cos(48^\circ) \approx 446 \mathrm{~km}$.

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