Because the area of a square is the length of one side multiplied by itself, the area of this square would be 39.0625.
But, this is not the answer that is asked for. The problem gives you 3 significant digits, so we need to round 39.0625 to 3 significant digits. This would be 39.1 square feet.
$17.49 because you multiply 22 by .25 getting 5.5. You subtract that from the original 22 getting 16.5 which you then multiply by the sales tax .06. Add the tax amount to the 16.5 to get 17.49.
