\[\boxed{\mathbf{2.555}}\]
\[\textbf{а)}\ \frac{\frac{3}{4}}{\frac{9}{16}} = \frac{\frac{3}{4} \cdot 16}{\frac{9}{16} \cdot 16} = \frac{12}{9} = \frac{4}{3} = 1\frac{1}{3}\]
\[\textbf{б)}\ \frac{7}{\frac{3}{5}} = 7 \cdot \frac{5}{3} = \frac{35}{3} = 11\frac{2}{3}\]
\[\textbf{в)}\ \frac{\frac{5}{9}}{2} = \frac{5}{9} \cdot \frac{1}{2} = \frac{5}{18}\]
\[\textbf{г)}\ \frac{6,5}{1,3} = \frac{65}{13} = 5\]