Find how many piranhas you can put in a cylindrical tank
whose diameter is 4 feet and whose height is 1.25 feet if
each piranha needs 1.5 cubic feet of water.

The correct answer is 10 piranhas.

Step-by-step explanation:

To calculate the total Volume of a cylinder we have to use the following formula:

Volume = Area * Height

Area = π * r²  , where r= radius

The diameter is always the twice the radius so the diameter is 4 feet in this case and the radius is 2 feet  so the area is

Area= 3.1416 * (2*2)

Area = 3.1416 * 4

Area = 12.5664 square feet

Volume = 12.5664 (area) * 1.25 (height).

Volume = 15.708 cubic feet

Each piranha needs 1.5 cubic feet so we have to divide the total Volume by the volume that each piranha needs

15.708/ 1.5 = 10.472 or ten pirahnas because we can't put a fraction of a piranha in the tank.