How many square feet does a 13x13 tile cover?

Answer 1

I assume that the tile is a square of 13 inches by 13 inches. There are exactly 12 inches in 1 foot, so 13 inches is (13 inches)*(1 foot / 12 inches) = 13/12 feet. The "inches" units cancel out; this type of procedure can be used with any units based on ratios.

So we have a 13/12 foot by 13/12 foot square tile. To get the area of this tile, we just recall that the area of a square is just the square of the length of a side (just multiply the length of any side by itself). That means the area of this tile is (13/12)^2 square feet, or 169/144 square feet. If we perform the division to get decimal notation, we get 1.17361... square feet. Since we only have 2 significant digits in our initial information (the tile company cannot make tiles that are exactly 13 inches on each side, the real length is greater than or less than 13 inches by an unknown amount), we can only have at most 2 significant digits of accurate information in our result. If the original length is very close to exactly 13 inches, then the area should be close to 1.17361... square feet. The closest area with 2 significant digits to that area is 1.2 square feet.