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Find the surface area of the following rectangular prism.
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Surface area is adding the area of all of the faces together.
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But instead of adding them one by one, they actually kind of come in pairs.
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There are two of these and they are both 11 by nine feet.
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And the area of a rectangle is length times width.
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So we need to take 11 times nine.
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But like we said, there are two of them. so we need to multiply by two and now we will add the next pair.
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Here, we have the two pink rectangles.
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They are nine by 18 feet.
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So we take two times nine times 18.
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And our last pair will be the top and bottom and they are 11 by 18 feet.
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So we have two times 11 times 18.
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So we have two times 99 plus two times 162 plus two times 198, which equals 198 plus 324 plus 396, which equals 918 feet square since this is an area.