\[\sqrt{x} = 1\frac{3}{5}\]
\[\sqrt{x} = \frac{8}{5}\]
\[x = \left( \frac{8}{5} \right)^{2}\]
\[x = \frac{64}{25} = \frac{256}{100}\]
\[x = 2,56.\]
\[Ответ:число\ 2,56.\]