The area for a trapezoid is A = 1/2 h (base 1 + base 2). You have the top base of 8. But straight down underneath that is also a base of 8. Next to that 8 you have a 4, so thus far you have a bottom base of 8 + 4. But you're missing what's over on the left. That base measure of that triangle is also 4, because the triangles are congruent. So the whole bottom base is 4 + 8 + 4 = 16. Now you have everything you need: A = 1/2 (6) (8 + 16). Do the addition inside the parenthesis first to get 24. Now multiply that by 6 to get 144. Now finally, divide that by 2 to get 72 cm^2