All the sides of a square are equal.
Perimeter of a square = 4(measure of 1 side)
Therefore if a square contains 4 sides, and the measure of one side is 2 inches, the perimeter is 8 inches. (2x4)
The definition of directly proportional is when one substance increases at the same rate of another substance. When a number is plugged into our formula, the perimeter increases.