a dolphin swims 665,280 feet in 3 hours. use the formula d = rt, where d represents distance, r represents rate, and t represents time, to answer the following questions. show your work.

part a: rearrange the distance formula, d = rt, to solve for rate.
part b: find the dolphin's rate in feet per hour.

part c: find the dolphin's rate in miles per hour.

part d: which unit, feet, or miles, makes more sense to use in this scenario, and why?