Answer:
1504 ft²
Explanation:
The surface area is the sum of the areas of the 6 rectangular faces. Opposite faces are congruent, so you only need to find the areas of three of them, then double the result. This is summarized in the formula ...
SA = 2(LW +WH +LH)
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This can be simplified slightly to ...
SA = 2(LW +H(L +W))
It does not matter which dimensions you assign to L, W, and H.
SA = 2((12 ft)(16 ft) + (20 ft)(12 ft +16 ft)) = 2(192 ft² +(20 ft)(28 ft))
= 2(192 ft² +560 ft²) = 2(752 ft²)
SA = 1504 ft²
The surface area of the rectangular prism is 1504 square feet.