Answer:
2/3
Step-by-step explanation:
Surface area is ...
... S = 2πr² + 2πrh = 2πr(r+h)
Volume is ...
... V = πr²h
Then the ratio of surface area to volume is ...
... S/V = (2πr(r+h))/(πr²h) = 2(r+h)/(rh)
For r= 4 and h=12, this ratio is
... S/V = 2(4 +12)/(4·12) = 2/3
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Comment on this ratio
Unlike many ratios, this ratio is not a pure number. It has units of 1/ft. That means the ratio would be different if the dimensions of the cylinder were expressed in different units. If the dimensions were in inches, for example, the ratio would be 1/18 per inch.
