Side length of small squares = 3 cm
Therefore area of 1 small square = 3 x 3 = 9 cm²
Given total Area = 72 cm²
Therefore no of small squares = 72/ 9 = 8 sqaures
Perimeter of one small square = 4a = 4 x 3 = 12 cm
Therefore total length = 12 x 8 = 96 cm