The surface area is the sum of the areas of all the faces of the rectangle.
We have three different rectangles here, each of which occur twice within the shape: 3 x 2, 6 x 2, 6 x 3
3 x 2 = 6 || 6 x 2 = 12
6 x 2 = 12 || 12 x 2 = 24
6 x 3 = 18 || 18 x 2 = 36
Now that we have all of the areas, we need to add them up.
12 + 24 + 36 = 72
Answer: 72 sq cm
Hope this helps!
