第29页

信息发布者:
18
16
20
1

$1:2=2:4$
64
10
$0.6:4=9:60$
$0.6:1=36:60$
D
B
$\frac{7}{40}$
$\frac{2}{5}:\frac{4}{7}=\frac{7}{40}:\frac{1}{4}$
$\frac{32}{35}$
$\frac{2}{5}:\frac{1}{4}=\frac{32}{35}:\frac{4}{7}$
$\frac{5}{14}$
$\frac{1}{4}:\frac{2}{5}=\frac{5}{14}:\frac{4}{7}$
$12:9=2:1.5;$$9:12=1.5:2;$$12:2=9:1.5;$$2:12=1.5:9;$$1.5:9=2:12;$$9:1.5=12:2;$$1.5:2=9:12;$$2:1.5=12:9$