4,2 : m = 2 1/3 : 3 1/8
21/5 : m = 7/3 : 25/8
m · 7/3 = 21/5 · 25/8 - свойство пропорции
m · 7/3 = 105/8
m = 105/8 : 7/3
m = 105/8 · 3/7
m = 45/8
m = 5 целых 5/8Проверка:
21/5 : 45/8 = 7/3 : 25/8
21/5 · 8/45 = 7/3 · 8/25
168/225 = 56/75
0,74(6) = 0,74(6) - верно.
