Solve the problem.
-The air speed of an airplane is $640 \mathrm {~km} / \mathrm { hr }$ and its angle of climb is $9.13 ^ { \circ }$. What is its ground speed (to the nearest $\mathrm { km } / \mathrm { hr } )$ ?
A) $632 \mathrm {~km} / \mathrm { hr }$
B) $617 \mathrm {~km} / \mathrm { hr }$
C) $622 \mathrm {~km} / \mathrm { hr }$
D) $627 \mathrm {~km} / \mathrm { hr }$

Question

Quizplus · Accepted Answer

The ground speed of the airplane can be found by multiplying its air speed by the cosine of its angle of climb. Thus, ground speed = $640 \times \cos(9.13^\circ)$. Calculating this gives a value close to $632 \mathrm {~km} / \mathrm { hr }$, rounding to the nearest kilometer per hour.

Solve the Problem 640 km/hr640 \mathrm {~km} / \mathrm { hr }640 km/hr

Solve the Problem $640 \mathrm {~km} / \mathrm { hr }$