The nucleus of an atom is spherical. The relation between radius of the nucleus and mass number $\mathrm{A}$ is given by $\text{1.25}\times \text{1}{\text{0}}^{-\text{13}}\times {\mathrm{A}}^{\frac{1}{3}}\mathrm{ }\mathrm{c}\mathrm{m}$ . If radius of atom is one $\mathrm{\AA }$ and the mass number is 64, then the fraction of the atomic volume that is occupied by the nucleus is $\left(\mathrm{x}\right)\times 10^{-13}$ . Calculate $\mathrm{x}$