Question 209297
From  statements  about  direct  and  indirect variation,,,
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R=k (L/d^2),,,where,,R= resistance(ohms),,,L=Length(ft),,,d=diameter(in)
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and  k is  a  constant  of  variation.

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From  example  given,,,R=k (100/.01^2) =80,,,or  k=.00008
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Question  is,,,R = k (90/.04^2)= .00008 (90/.04^2) = 4.5  ohms
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