problem: Bob can travel $m$ miles in $h$ hours on his bicycle. At this rate, how many hours would it take him to travel $h$ miles? Express your answer in terms of $m$ and $h$.
solution: Since Bob travels $m$ miles in $h$ hours, he travels $m/h$ miles in 1 hour.  Therefore, in order to travel $h$ miles, he must travel for $h/(m/h) = \boxed{\frac{h^2}{m}}$ hours.