[tex]5\frac{1}{4}:1\frac{3}{8}=\frac{21}{4}:\frac{11}{8}=\frac{21}{\not4^1}* \frac{\not8^2}{11}=\frac{21*2}{11}=\frac{42}{11}=3\frac{9}{11}[/tex] or [tex]5\frac{1}{4}:1\frac{3}{8}=\frac{5.25}{1.375}=\frac{5250}{1375}=\frac{42}{11}=3\frac{9}{11}[/tex]