21*3 = 63 square feet.
7 × 3 = 21 square feet
It is 2.1875 square feet.
Oh, dude, you're hitting me with the math questions now? Alright, so if you have a room that's 18 feet by 21 feet, you just gotta multiply those two numbers together. That gives you 378 square feet. So, like, if you're planning on redecorating or something, now you know how much paint you need.
304.5 square feet. This is an easy calculation - just multiply the length in feet by the width in feet. The answer is the number of square feet.
21 x 21 = 441 square feet
21 feet times 19 feet = 399 square feet
20x21= 420, so the answer is 420 square feet.
178.5 square feet (8.5 x 21 = 178.5).
26*21 = 546 sq feet
21*19 = 399 square feet.
37.3 square yards.
If the given dimensions are in feet then 21 times 12 = 252 square feet
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.
21 x 11 = 231 -- There are 231 square feet on the floor. -- There are 231 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.
Area = Length * Width 21 * 40 = 840 Square Feet
21 square feet (7'x3') = 1.95 square meters.