Question

Suppose two bicyclists start at the same location.

Answer 1

Answer:

  4 mi/h

Step-by-step explanation:

The distance between the cyclists is the hypotenuse of an isosceles right triangle. The hypotenuse is √2 times the length of the legs in such a triangle, so each cyclist must have ridden 8 miles in 2 hours.

Their speed is (8 mi)/(2 h) = 4 mi/h.

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Additional comment

Consider an isosceles right triangle with leg lengths 1. Then the Pythagorean theorem tells us the length of the hypotenuse is ...

  c² = a² +b² . . . square of hypotenuse is sum of squares of legs

  c² = 1² +1² . . . . both legs are 1 in our example triangle

  c² = 2

  c = √2

That is, the hypotenuse is √2 times the leg length.