Вычислите: 1) \(\frac{21}{40} : \frac{3}{4}\) 2) \(1\frac{5}{9} : 1\frac{8}{27}\) 3) \(5 : \frac{15}{16}\) 4) \(\frac{9}{17} : 3\)

1) \(\frac{21}{40} : \frac{3}{4} = \frac{21}{40} \cdot \frac{4}{3} = \frac{21 \cdot 4}{40 \cdot 3} = \frac{7 \cdot 1}{10 \cdot 1} = \frac{7}{10}\) 2) \(1\frac{5}{9} : 1\frac{8}{27} = \frac{14}{9} : \frac{35}{27} = \frac{14}{9} \cdot \frac{27}{35} = \frac{14 \cdot 27}{9 \cdot 35} = \frac{2 \cdot 3}{1 \cdot 5} = \frac{6}{5} = 1\frac{1}{5}\) 3) \(5 : \frac{15}{16} = 5 \cdot \frac{16}{15} = \frac{5 \cdot 16}{15} = \frac{1 \cdot 16}{3} = \frac{16}{3} = 5\frac{1}{3}\) 4) \(\frac{9}{17} : 3 = \frac{9}{17} \cdot \frac{1}{3} = \frac{9 \cdot 1}{17 \cdot 3} = \frac{3 \cdot 1}{17 \cdot 1} = \frac{3}{17}\)