A cylindrical aquarium has a 10 foot diameter and an 18 foot height and holds 10,400 gallons of water. What is the aquariums's volume in cubic feet?

volume of cylinder = π(5^2)(18) = appr. 1413.7 cubic feet.

( If I recall my non-metric times, 1 cubic foot is about 7.5 US gallons, so the above would be around 10600 gallons. Which makes sense, since you would not fill the aquarium to the very top)