SOLUTION: John leaves an intersection at 12 noon and heads North at 28 miles per hour, while Jane leaves the intersection at the same time and heads West at 21 miles per hour. Find an ex

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Question 519295: John leaves an intersection at 12 noon and
heads North at 28 miles per hour, while Jane
leaves the intersection at the same time and
heads West at 21 miles per hour.
Find an expression d for their distance
apart (in miles) after t hours.

Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
They are going at right angles, so the distance between them "as the crow flies" is the hypotenuse.
.
d = r*t is the basic distance equation
.
John's r = 28 mph
Jane's r = 21 mph
.
They leave at the same time, so John's time ('t') = Jane's time.
.
Applying the Pythagorean Theorem:
.
+d+=+sqrt+%28++%2821t%29%5E2+%2B+%2828t%29%5E2+%29+
.
Done.