You can't, cubic feet is a three dimensional measure, feet is a two dimensional measure.
Normal feet measure distance, cubic feet measure volume. Square feet measure area. This is not a difference in size, it is a difference in dimension. Distance is one dimensional, volume is three dimensional.
Cubic feet measure volume. It is not possible to measure the number of feet in cubic feet. Cubic feet are in three dimensions. Feet are in one dimension. (And square feet are in two dimensions.)
Unit of imperial measure. Is about three feet long.
43 inches
Your question makes no sense.feet are a measure of length, whereascubic feet are a measure of volume.Volume has three dimensions, each of those dimensions being a length.
Square feet measure area, and yards measure length. If you mean FEET in 21 yards, the answer is 63 (3 times 21). If you mean square feet in 21 SQUARE YARDS, the answer is 189 (three times three times 21).
To measure cubic feet, you would have to measure in three directions - length, width, and height - measuring in just two will produce square feet.
a yardstick is a stck used to measure and is equivalent to three feet
Square feet is a measure of two-dimensional area. Cubic feet are three-dimentional. One cannot be converted to the other.
A yeard is an alternative word for a yard, a measure of length equal to three feet.
These are two different forms of measurements: feet are a measure of distance, while years are a measure of time. If, however, you meant to ask how many feet are in a yard, the answer is three.