21 x 4 = 84
-- There are 84 square feet on the floor.
-- There are 84 square feet on the ceiling.
-- There are a lot more square feet on the walls, but in order to
calculate them, you need to know the height of the room.
108 square feet
165 square feet
360 square feet.
144 square feet.
288 square feet.
There are 66 square feet.
234 square feet.
There is 121 square feet in a 11'x11' room.
There are 270 square feet in a 15'x18' room.
A room measuring 20' x 20' = 400 square feet
The room is 144 square feet.
60 square feet