The perimiter is 4 times as great as the lenght of any of its sides means that:
4 a (perimiter) = 4 a (4 times any of the sides)
It means that one side is 1/4 of the perimeter:
a = 1/4 4a
a = a
Answer: Perimeter is proportional to the side length by Perimeter = 4 Sides or Side = 1/4 Perimeter.