KCl crystallizes in the same type of lattice as does $NaCl$ . Given that $\large\frac{r_{Na^{+}}}{r_{cl^{-}}}$$=0.5$ and $\large\frac{r_{Na^{+}}}{r_{K^{+}}}$$=0.5$ calcute the ratio of the unit cell for $KCl$ to that for $NaCl$

Question

$\begin{array}{1 1} 103.5 \\ 1.143 \\ 8.4 \\ 9.5 \end{array} $