1223.65 cm^2
You multiply base (20) X height (20) for the squares. and since you can see 5 squares, it's 20 x 20 x 5 = 2000
then you do 20 x 20 + 20 x the square root of [(20/2)^2 +(18^2) + (20^2)] TIMES the square root of [(20/2)^2 + 18^2)] so you get about 1223.65cm^2
