\[\boxed{\mathbf{2.574}}\]
\[\textbf{а)}\ 54\ :0,45 = 5400\ :45 = 120\]
\[\textbf{б)}\ 4,4\ :\frac{11}{20} = \frac{44}{10} \cdot \frac{20}{11} = 4 \cdot 2 = 8\]
\[\textbf{в)}\ 2\frac{4}{5}\ :0,7 = \frac{14}{5}\ :\frac{7}{10} =\]
\[= \frac{14}{5} \cdot \frac{10}{7} = 2 \cdot 2 = 4\]