Answer: 196
Step-by-step explanation:

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Formula
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Volume = πr²h
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Find Volume of one tank
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Volume of 1 tank = πr²h
Volume of 1 tank = 3.14 x 6² x 12
Volume of 1 tank = 678.24 ft³
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Find Volume of 5 tanks
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Volume of 1 tank = 678.24
Volume of 5 tanks = 678.24 x 5
Volume of 5 tanks = 3391.2 ft³
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Answer: 3391.2 ft³
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Think of the "of" as a multiplication sign:
(.15)(12)= 1.8 meters
There you go! hope this helps with this problem and future ones.