Найдите неизвестный член пропорции x: 20=2: 5 x: 18=2: 3 5: 9=15: × x: 18=7: 9 6: x=3: 7 12: 7=60: x

X/20 = 2/5
5x = 40
x = 8
x/18 = 2/3
3x = 36
x = 12
5/9 = 15/x
5x = 135
x = 27
x/18 = 7/9
9x = 126
x = 14
6/x = 3/7
3x = 42
x = 14
12/7 = 60/x
12x = 420
x = 35