382 cubic inches of it.
One foot
A 12 inch Nerf ball typically weighs around 6 to 8 ounces.
volume of a sphere (the ball) = 4/3*pi*radius3 volume of box - volume of sphere = space remaining 27 - 4/3*pi*1.53 = 12.86283306 space remaining is about 13 cubic inches
One
One square inch
4 square feet are needed
155520 sq inch
1 half of a inch
54in
It depends on the size of the fountain. You have to calculate the height, depth, and width to figure out how much space is needed.
30'
All of it.