The radius of $2^{\text{nd}}$ orbit of $\mathrm{He}^+$ of Bohr's model is $r_1$ and that of fourth orbit of $\mathrm{Be}^{3+}$ is represented as $r_2$. Now the ratio $\frac{r_2}{r_1}$ is $x:1$. The value of $x$ is $\_\_\_\_$.
The radius of $2^{\text{nd}}$ orbit of $\mathrm{He}^+$ of Bohr's model is $r_1$ and that of fourth orbit of $\mathrm{Be}^{3+}$ is represented as $r_2$. Now the ratio $\frac{r_2}{r_1}$ is $x:1$. The value of $x$ is $\_\_\_\_$.