"Feet" is a unit of length or distance. "Cubic feet" is a unit of volume or capacity.
The two units are used to describe two completely different kinds of quantities,
and neither of them can be converted to the other one.
If volume could be converted into length, you'd be able to figure out how many
yards of gas you put in your car last week.
500 cubic feet
64 cubic feet
12 ft * 72 ft * 12 ft = 10368 cubic feet.
That is 18 cubic ft.
That is 67,200 cubic ft.
1375 cubic feet will create an object that is 11.2 ft. x 11.2 ft. x 11.2 ft.
75 cubic feet
100 cu ft × 2 = 200 cu ft.
8*4*1.6 = 51.2 cubic feet
100*20*2 = 4000 cubic feet
That is 187.5 cubic ft.
100 ft * 250 ft * 12 ft = 100*250*12 cubic ft = 300000 ft3