A wire of length $10 \mathrm{~cm} and radius \sqrt{7} \times 10^{-4} \mathrm{~m} connected across the right gap of a meter bridge. When a resistance of 4.5 \Omega is connected on the left gap by using a resistance box, the balance length is found to be at 60 \mathrm{~cm} from the left end. If the resistivity of the wire is \mathrm{R} \times 10^{-7} \Omega \mathrm{m}, then value of \mathrm{R}$ is :