Question

реши уравнение: 2 1/7 : b = 2 19/28 : 3 3/4

Answer 1

2 1/7:b=2 19/28: 3 3/4
2 1/7:b = 2 19/28 : 3 21/28
2 1/7:b = 75/28*28/105
2 1/7:b =5*1/7
2 1/7:b = 5/7
b=15/7*7/5
b=3

Answer 2

а можно основным правилом пропорций?..