explanation: the easiest way is to separate one of the diagonals into a triangle and use the pythagorean theorem. a^2 + b^2 = c^2 4^2 + 3^3 = c^2 16 + 9 = c^2 25 = c^2 5 = c you now know that both of the diagonals have a length of 5. by counting the units on the two straight, you know that their length is 6. 6 + 6 + 5 + 5 = 22
