The answer is: " 318 cm² " .
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Explanation:
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This is a rectangular prism.
The [lateral] surface area of a prism has 6 sides.
Every side of a rectangular prism has a "corresponding side" with the same [lateral] surface.
So, we take the [lateral] surface area of one side of the rectangular prism (i.e. "length * width" ) ; and multiply that by "2".
Then we take the [lateral] surface area another side [that is DIFFERENT from the (aforementioned 2 sides— i.e. "length * width)] ; and multiply that value by "2" .
Finally, we take the [lateral] surface area of another side [that is DIFFERENT from the (aforementioned 4 sides— i.e. "length * width)] ; and multiply that value by "2" .
Then, we add these values —the values of these "lateral surface areas"—together; to get the total [lateral] surface area of the entire rectangular prism.
As such:
2(9 cm * 6 cm) + 2(7 cm * 9cm) + 2(6cm *7cm) ;
= 2(54 cm²) + 2(63 cm²) + 2(42 cm²) ;
= 108 cm² + 126 cm² + 84 cm² ;
= 234 cm² + 84 cm² ;
= 318 cm² .
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