\[\boxed{\mathbf{2}\mathbf{.}\mathbf{157}}\]
\[\mathbf{OS = 26;\ \ ON = 13.}\]
\[\textbf{а)}\ ON\ короче\ \text{OS\ }на:\ \]
\[OS - ON = 26 - 13 =\]
\[= 13\ единичных\ отрезков.\]
\[\textbf{б)}\ ON\ короче\ \text{OS\ }в:\]
\[OS\ :ON = 26\ :13 = 2\ раза.\]