The way you find the area of a square is by multiplying one side by another, and since it is a square, the sides are the same. This means that if we have a square with a side length of x, the way to find the area of that square is to multiply x by x, which can be written as . Now, since we're doubling this, we can say that double Mary's garden is . If we substitute 8 in for x, we have to multiply by 2 or 8 by 8 by 2 to find our answer. 8 times 8 is 64 and 64 times 2 is 128.
