\[\boxed{\mathbf{2.}\mathbf{184}}\]
Решение.
\[1)\ \frac{17}{50} + \frac{3}{50} = \frac{20}{50} = \frac{2}{5}\ (м) -\]
\[сторона\ \text{BC.}\]
\[2)\ \frac{17^{\backslash 5}}{20} - \frac{17^{\backslash 2}}{50} - \frac{2^{\backslash 20}}{5} =\]
\[= \frac{85}{100} - \frac{34}{100} - \frac{40}{100} =\]
\[= \frac{11}{100}\ (м) - сторона\ AC.\]
\[Ответ:\ \frac{11}{100}\ м.\]