If the given dimensions are in feet then 21 times 12 = 252 square feet
400 square feet.
The area of a 12x10 room is 120 square feet.
40 square yards
There is 121 square feet in a 11'x11' room.
There are 270 square feet in a 15'x18' room.
A 20' by 14' room measures 31.1 square yards.
234 square feet.
240 square feet
9.29 square meters
162 square feet.
525 square feet.
300 square feet.