First, surface area will be measured in cm^2 (area), not cm^3 (volume).

Second, the formula for the barrel surface area is incorrect. The “sides” are calculated correctly but there should be two “ends” at Pi*(Dh/2)^2 (formula for area of a circle), not the Pi*Dh that is listed (formula for circumference of a circle). So the total surface area formula should be:

Pi*L*(Db+Dh/2) + 2 [Pi*(Dh/2)^2]

Cheers!

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