\[\boxed{\mathbf{699\ (699).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[4 = \sqrt{16}\]
\[3\sqrt{2} = \sqrt{18}\]
\[\sqrt{16};\sqrt{17};\sqrt{18} \Longrightarrow 4;\ \ \sqrt{17};\ \ \ \]
\[3\sqrt{2}.\]