5:3=ｘ:15

(a)  

7:ｘ=133:38

(a)  

5:3=ｘ:120

(a)  

3:4=1.5:ｘ

(a)  

7:8=ｘ:2

(a)  

2.4:ｘ=12:20

(a)  

4.8:3.2=ｘ:4

(a)  

ｘ:28=18:8

(a)  

2:3.6=4:ｘ

(a)