\[\boxed{\mathbf{318.}}\]
\[\textbf{а)}\ S = \sqrt{25} = 5.\]
\[\textbf{б)}\ S = \sqrt{121} = 11.\]
\[\textbf{в)}\ S = \sqrt{3,24} = 1,8.\]
\[\textbf{г)}\ S = \sqrt{1,69} = 1,3.\]