we need to find the surface area of the shapes before adding them together. the triangles are 6*4 and since there are two, we do not need to divide by 2. (normally to find the area of a triangle it is base times height divided by 2)
so the area of the triangles are 24 units. Next we have the outer rectangles. 7*5=35. Since there are 2, we multiply by 2. Last we have the middle rectangle. 7*6=42.