Answer:
12 inches
Step-by-step explanation:
Since you know your multiplication tables, you know that 57 = 3·19, so the wire is 3 cents for each inch. Then you also know that 36 = 3·12, so 12 inches of wire will cost 36 cents.
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You can also write the proportion ...
19 in/(57 cents) = x/(36 cents)
Multiplying by 36 gives
x = (19 in)·36/57 = 12 in
