Вычислите: \(\frac{1}{6}:\frac{2}{5}\); \(\frac{2}{9}:9\); \(17:43\); \(21:\frac{3}{7}\); \(4\frac{2}{3}:3\frac{8}{9}\).

1. \(\frac{1}{6}:\frac{2}{5}=\frac{1}{6}\cdot\frac{5}{2}=\frac{5}{12}\).
2. \(\frac{2}{9}:9=\frac{2}{9}\cdot\frac{1}{9}=\frac{2}{81}\).
3. \(17:43=\frac{17}{43}\).
4. \(21:\frac{3}{7}=21\cdot\frac{7}{3}=49\).
5. \(4\frac{2}{3}:3\frac{8}{9}=\frac{14}{3}:\frac{35}{9}=\frac{14}{3}\cdot\frac{9}{35}=\frac{6}{5}=1\frac{1}{5}\).

Ответ: \(\frac{5}{12};\ \frac{2}{81};\ \frac{17}{43};\ 49;\ 1\frac{1}{5}\).