Find the area: you can split the figure into two rectangles.
The rectangles will be 7*20 and 7*11. The areas of those are <em>140 cm² and 77 cm²</em>. Add those up, and you get 217 cm².
Find the surface area: you can also split the net (the figure's surface area represented in a two-dimensional form) into two congruent triangles and three congruent rectangles. the triangles' area is <em>2(1/2*10*8) = 80 cm²</em>. The rectangles' area is <em>3(18*8) = 432 cm²</em>. Those totaled is 512 cm².
