Question 173158
I'm not sure if this is a cube or not, but the following works whether the l, w, and h are equal or different from one another. There are 6 sides and the sides opposite each other have the same area, so if you calculate the area of one side you must double it to have the area contributed by the 2 opposite sides. 


If the dimensions of the solid are L, w, and h, the formula for the area of the ends of the figure would be L * w. The area of one side is w * h and the other is L * h. The 5 in your diagram is either L, w, or h and you can substitute it in for that variable. 


The surface area for the whole figure would be:
2(L * w) + 2(w * h) + 2(L * h) or
2Lw + 2wh + 2Lh