\[\boxed{\mathbf{2.567}}\]
\[1\frac{1}{13}\ :c = \frac{14}{13}\ :c = \frac{14}{13c}\]
\[c = 1:\]
\[\frac{14}{13 \cdot 1} = \frac{14}{13} = 1\frac{1}{13}.\]
\[c = \frac{2}{13}:\]
\[\frac{14}{13 \cdot \frac{2}{13}} = \frac{14}{2} = 7.\]
\[c = 1\frac{1}{7} = \frac{8}{7}:\]
\[\frac{14}{13 \cdot \frac{8}{7}} = \frac{14 \cdot 7}{13 \cdot 8} = \frac{49}{52}.\]
\[c = \frac{14}{9}:\]
\[\frac{14}{13 \cdot \frac{14}{9}} = \frac{14 \cdot 9}{13 \cdot 14} = \frac{9}{13}.\]
\[\frac{9}{13} = \frac{36}{52} < \frac{49}{52} < 1\frac{1}{13} < 7.\]