Question

two planes leave an airport at the same time. Their speeds are 320 miles per hour and 380 miles per hour. If the angle between their courses is 112 degrees, how far apart are they after two hours? (The hint is using the law of cosines)

Answer 1

after 2 hours, they have traveled 640 and 760 miles. At that point, the distance d between them is

d^2 = 640^2 + 760^2 - 2(640)(760) cos 112°
d = 1163 mi