????$\frac {1}{4}:$????????$\frac {1}{8}=\frac {1}{4}\div \frac {1}{8}=2$????
????$ 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:$????????$24,$????
????$5:$????????$\frac {5}{2}=48:$????????$24$????