\[\boxed{\text{5.367.}}\]
\[\frac{3}{12} = \frac{1}{4} = \frac{4}{16}\ \]
\[\frac{12}{24} = \frac{1}{2} = \frac{8}{16}\ \]
\[\frac{21}{56} = \frac{3}{8} = \frac{6}{16}\ \]
\[\frac{27}{36} = \frac{3}{4} = \frac{12}{16}\text{\ \ }\]