Hi There!
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Question #4:
4 x 3 x 2 = 24in.
Answer: 24 in.
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Question #5:
4.8 x 5 x 3 = 72in.
Answer: 72in.
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Question #6
Answer: 93.593mm
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Question #7:
(12 x 8.1)+ (8.1 x 4.05 / 2) = 21.1in.
Answer: 98.2in.
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Question #8:
(3.5 * 18 * 2) + 2.5 = 128.5ft.²
Answer: 128.5ft.²
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Question #9:
Height: 2ft.³
Width: 4ft.³
Length: 10ft.³
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Hope This Helps :)