Ответ:

  1. \(\frac{3}{4}:\frac{5}{7}=\frac{3}{4}\cdot\frac{7}{5}=\frac{21}{20}=1\frac{1}{20}\);
  2. \(\frac{5}{18}:\frac{25}{27}=\frac{5}{18}\cdot\frac{27}{25}=\frac{3}{10}\);
  3. \(\frac{9}{16}:\frac{3}{64}=\frac{9}{16}\cdot\frac{64}{3}=12\);
  4. \(\frac{25}{72}:\frac{4}{63}=\frac{25}{72}\cdot\frac{63}{4}=\frac{175}{32}=5\frac{15}{32}\).