Lets go ahead and calculate the area of each side; added together, this will give us the full surface area. First the base, which is 9 by 9 and a square. This means its area is 9*9, which equals 81. Next the triangles, which are all the same, so we only have to do it once and then add it 4 times at the end. The area of a triangle is (1/2)bh, so (1/2)(9)(7) = 31.5.
Finally, we just need to add the areas up.
81 + 31.5 + 31.5 + 31.5 + 31.5 = 81 + 4(31.5)
81 + 126 = 207 units^2
