?$\frac {1}{4}$?:?$\frac {1}{8}=\frac {1}{4}\div \frac {1}{8}=2$?,?$0.45$?:?$0.9=0.45\div 0.9=0.5$?
?$5$?:?$\frac {5}{2}=5\div \frac {5}{2}=2$?,?$48$?:?$24=48\div 24=2$?
?$\frac {1}{3}$?:?$\frac {1}{3}=\frac {1}{3}\div \frac {1}{3}=1$?
組成的比例有:?$\frac {1}{4}$?:?$\frac {1}{8}=5$?:?$\frac {5}{2}$?,?$\frac {1}{4}$?:?$\frac {1}{8}=48$?:?$24$?,?$5$?:?$\frac {5}{2}=48$?:?$24$?