Ok so to find the area of two sides (LengthHeight)2 sides, we are going to require to find the area of adjacent sides (WidthHeight)2 sides, so find the area of ends (LengthWidth)2 ends, Now it's time to integrate the three areas together in order to find the surface of the area. Okay so the surface area of a rectangular prism 5 cm long, 3 cm. wide and 2 cm. high = 522 + 322 + 532 = 20 + 12 + 30 = 62 cm2
Cube= 2ab+2bc+2ac
The area for top and bottom is (side lengths a and c) = ac. So as we look at it there are at least two of them, so you'd get 2ac. Now for the front and back we have the side length of b and c, so the area of one of them is bc, so as we look at it there are two of then. The surface area of those two is 2bc. Left and right sides have a side length of a and b, so of course the surface area of one of them is a*b. There are two of them, and from that their combined surface area is 2ab.
