L= length of one side of the square
Ok so we know the perimeter is 32 cm. Perimeter is the sum of all the sides of a shape. Now all four sides of a square are the same length. That means 4*L=32.
Now that we have the equation 4*L=32, we need to find a number that when multiplied by four, equals 32. Since 4*8=32, we know the answer must be 8cm.