For this problem you can do it one of two ways. The first way would be simply take the square root because the area of a square is one side squared. The other way using the same rule would be to go up from a reasonable number and square it, if that is not the number you are looking for add 1 to the original number and square it again. if you cannot square and square root in your head, you should be allowed to use a calculator to get the answer or 17 as the length of a side.