Answer
The graph is on the figure. The resistance is reduced by the factor of $4$ when we double the thickness of the wire.
Work Step by Step
Using Wolfram Mathematica we get the graph shown on the figure.
When the diameter is doubled the resistance is reduced by the factor of $4$. To show this suppose that we have two wires, one of diameter $x$ and the other of diameter $x'=2x$. We calculate their resistances using the formula in the problem:
$$y=\frac{10.770}{x^2},\quad y'=\frac{10.770}{(x')^2}=\frac{10.770}{(2x)^2} = \frac{10.770}{4x^2}.$$ Looking at the final expressions we see that $y'$ is just $y$ divided by $4$.
