Let's say we want to find th esurface area of this rectangular prism. The first thing we need to realize is the best way to find a surface areea is to find out how many different faces there are on the shape. Now we can see here that this face, this face and this face are unique. But in fact, if you were to go around the shape, you'd see that you'd find this face at the end, this one on the other side here and finally this one on the bottom. So we know that we can find the area of this face, this face, and this face, if we add those together and multiplied by 2, that will give us our total surface area. So, let's add in some dimensions for our example. Let's say that here, it was 2 centimeters, and here, it was 5 centimeters, and finally this dimension here is 8 centimeters. Let's make that a bit clearer. First of all, let's start with this one. The area of this shape, because it's a rectangle is simply 2 multiplied by 5. so the area of 1, I've labeled it 1, is equal to 10 centimeters squared. Remember it's centimeters squared because we're dealing with an area. Let's work out the area of this one. So the area of 2 is equal to this length here, which is 8 centimeters multiplied by this length here, which is 5 centimeters. 8 multiplied by 5 is 40 and we have centimeters squared, once again. Finally, let's work out the area of that face. The area of 3 is equal to this length here, 8, multiplied by this 2 here, because that is the same length as this bit. So, 8 multiplied by 2 is 16 centimeters squared. We add these up and that will give us 66 centimeters squared. The final step is to multiply this 66 by 2, giving us 132 centimeters squared.I'll just write that step there.we multiplied this by 2 and this here is our final area. This is the surface area of the prism. Just to recap, to find the toal surface area, we find the area of each individual face and realize that each face shows itself again once more on the shape. Which means if we add together all these areas and times that by 2, as have here, that will give us the total surface area of the prism. And that's how we find the total surface area of a rectangular prism. .

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