SOLUTION: I have some questions about resistance and inverse variation. The specific question is "The electrical resistance R of a wire varies inversely as the square of its diameter d. If a

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Question 1140414: I have some questions about resistance and inverse variation. The specific question is "The electrical resistance R of a wire varies inversely as the square of its diameter d. If a wire with a diameter of 3 millimeters has a resistance of 0.4 ohm, what is the resistance of a wire of the same length if its diameter is 2 millimeters?" This is on my last test study guide. I have no formula and the one on this site shows Length included in the formula and I don't have a measurement for length.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
R=k/d^2 is the formula where resistance R is proportional to (constant of proportionality is k) square of diameter d. Assume length will be the same with both.
0.4=k/3^2
0.4=k/9
k=3.6
use that in the next part.
R=3.6/2^2=3.6/4 =0.9 ohms