[tex]\bf \begin{cases}
1\frac{6}{7}\implies \cfrac{13}{7}\textit{ is to }13\implies &\cfrac{\frac{13}{7}}{13}
\\ \quad \\
1\frac{4}{7}\implies \cfrac{11}{7}\textit{ is to }11\implies &\cfrac{\frac{11}{7}}{11}
\end{cases}
\\ \quad \\\\ \quad \\
\cfrac{\frac{13}{7}}{13}=\cfrac{\frac{11}{7}}{11}\impliedby \textit{"a" proportion as "b" proportion}[/tex]
