Question

Akiko leaves the mall and drives directly west at a speed of 60 mph. At the same time, Kosuke leaves the mall and drives 40 degrees north of east at a speed of 45 mph. How far apart are they after 45 minutes? Round the answer to the nearest tenth of a mile.

A.17.4 miles

B.28.9 miles C.44.5 miles D.74.1 miles

Answer 1

you know that Akiko is 45 miles from the origin...Kosuke is (135/4) miles from the origin... You can draw a figure to clearly see the situation.

you "know" that the angle between their routes is 140º

the side opposite (140º) is the distance between them...

c^2 = (45)^2 + (135/4)^2 - 2(45)(135/4) cos 140

c ≈ 74.1 mile

Hope this answers the question.