220
You'll need 200 18-inch tiles.
22.2 tiles so buy 23 tiles.
266.666666666 so rounding up 267 tiles.
It is not clear what is meant by an "18x18 square feet" tile. 18ft * 18 ft = 324 square feet, so that one tile will be more than enough. An 18 inch by 18 inch tile cannot be a 18x18 square feet tile.
To determine how many 18x18 inch tiles you need for 56 square feet, first convert the tile size to square feet. An 18x18 inch tile is 1.5x1.5 feet, which equals 2.25 square feet per tile. Next, divide the total area needed (56 sq ft) by the area of one tile (2.25 sq ft): 56 ÷ 2.25 ≈ 24.89. Therefore, you will need 25 tiles to cover 56 square feet.
18" x 18" = 1.5' x 1.5' = 2.25 square feet90/2.25 = 40 tiles.
2.25 square feet
It depends on the units used for measuring the tiles. Obviously, the number of 18 inch x 18 inch tiles required will not be the same as 18 cm x 18 cm tiles. And if there were 18 yard x 18 yard tiles, you would need only 1.
5,184 2-square-inch tiles are needed.
875 24-inch tiles.
225 16-inch tiles.
144/(1.5*1.5) = 64 tiles, but if you are using this to determine how many are needed to tile a room, you need to add at least 10% for edging around the room. So, you probably need at least 71 or more tiles.