Divide 215 by 12=17 feet 11 inches
I think you have mis-stated your question. Square feet is an area, feet and inches is a length.
17.9 ft x 17.1 ft = 306.1 ft^2
84.6 inches
215 square feet is about 19.97 square meters.
215 Inches = 17.91595 Feet
215 inches=17.91 feet (or 17 feet 10 inches)
215 inches is 17.9167 feet.
215 inches is 18 (17.9166667) feet.
17.91666... feet in 215 inches.
17 feet 11 inches.
Divide 215 by 12=17 feet 11 inches
1cm is 0.394 inches. 21.5cm is (21.5*0.394) = 8.46 inches.
215
There are 12 inches in a foot. So 215 / 12 = 17 feet and 11 inches
17.9 feet.
215