Because all sides of a square are equal, and the perimeter is 20 in. We divide 20 by 4. This gives us 5 in. for each side. The area of a square is length times width, so we do 5x5. This means the area of the square is 25 square inches.
The first box is 3 more than the quotient of 6 and a number, the second is 6 less than the product of 3 and a number, the third box is the product of 6 and the sum of a number and 3.
