3. Выполните действия: a) \( \frac{3}{7} : \frac{7}{9} \) б) \( \frac{5}{15} : \frac{28}{42} \) в) \( \frac{6}{13} : \frac{9}{52} \) д) \( 2 \frac{3}{8} : \frac{13}{20} \) e) \( 3 \frac{3}{4} : 4 \frac{3}{8} \) г) 56 : \( \frac{7}{8} \)

a) \( \frac{3}{7} : \frac{7}{9} = \frac{3}{7} \cdot \frac{9}{7} = \frac{3 \cdot 9}{7 \cdot 7} = \frac{27}{49} \) б) \( \frac{5}{15} : \frac{28}{42} = \frac{1}{3} : \frac{2}{3} = \frac{1}{3} \cdot \frac{3}{2} = \frac{1 \cdot 3}{3 \cdot 2} = \frac{1}{2} \) в) \( \frac{6}{13} : \frac{9}{52} = \frac{6}{13} \cdot \frac{52}{9} = \frac{6 \cdot 52}{13 \cdot 9} = \frac{6 \cdot 4}{1 \cdot 9} = \frac{24}{9} = \frac{8}{3} = 2 \frac{2}{3} \) д) \( 2 \frac{3}{8} : \frac{13}{20} = \frac{19}{8} : \frac{13}{20} = \frac{19}{8} \cdot \frac{20}{13} = \frac{19 \cdot 20}{8 \cdot 13} = \frac{19 \cdot 5}{2 \cdot 13} = \frac{95}{26} = 3 \frac{17}{26} \) e) \( 3 \frac{3}{4} : 4 \frac{3}{8} = \frac{15}{4} : \frac{35}{8} = \frac{15}{4} \cdot \frac{8}{35} = \frac{15 \cdot 8}{4 \cdot 35} = \frac{3 \cdot 2}{1 \cdot 7} = \frac{6}{7} \) г) \( 56 : \frac{7}{8} = 56 \cdot \frac{8}{7} = \frac{56 \cdot 8}{7} = 8 \cdot 8 = 64 \) Ответ: a) \( \frac{27}{49} \) б) \( \frac{1}{2} \) в) \( 2 \frac{2}{3} \) д) \( 3 \frac{17}{26} \) e) \( \frac{6}{7} \) г) 64