answer: 22
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