1. Developing the formula for the Surface Area of a Prism

2. A Prism You can think of surface area as the area of the outside covering a 3-dimensional object. For instance, the amount of cardboard required for a cereal box.

3. A Prism Consider the following diagram. The diagram is a rectangular prism. Top and Bottom are Orange. Front and Back are Yellow. The 2 sides are Green.

4. The Net If we unfold the prism, you will see the prism unfolded, or the net.

5. The Net Compare how the sides match up:

6. Finding the Formula To determine the formula for finding the surface area of a rectangular prism, all we need to do is look at the shapes left over in the net:

7. Finding the Formula L h w h Look at the rectangles that are left. We need to find the area of each rectangle to find the surface area. w L L L w hh

8. Finding the Formula So, we have: SA = 2(Orange) + 2(Green) + 2(Yellow) SA = 2(Lw) + 2(wh) + 2(Lh)  the formula for the surface area of a prism must be: SA = 2Lw + 2wh + 2Lh We will use this for the rest of the unit.