Question

Speed of Plane A = 425 mph. Speed of Plane B = 375 mph. Both planes leave from Kansas City at the same time. Plane A flies due West. Plane B flies due South. After 3 hours, how far is Plane A from Plane B?

Answer 1

After 3 hours, Plane A has flown (425 mi/h)*(3 h) = 1275 mi.
After 3 hours, Plane B has flown (375 mi/h)*(3 h) = 1125 mi.

Since the distances flown are in directions that are at a right angle to each other, the Pythagorean theorem can be used to figure the separation. The distance between planes after 3 hours is
√(1275² +1125²) = √2,891,250 ≈ 1700.4

After 3 hours, Plane A is about 1700 miles from Plane B.