smc

Denote the side of one square as $s$. Then the diagonal of the second square is $s$, so the side of the second square is $\frac{s\sqrt{2}}{2}$. The area of the second square is $\frac{1}{2}{s}^2$, so the ratio of the areas is $\frac{s^2}{\frac{1}{2}{s}^2}=\boxed{2}$.