Comparison of Ratios and Compounded Ratio

i). Comparison of Ratios:
When we say that a:b > c:d, then it means
\begin{aligned}
\frac{a}{b} > \frac{c}{d}
\end{aligned}

ii). Compounded Ratio:
The compounded ratio of the ratios: (a : b), (c : d), (e : f) is (ace : bdf)

Please note it is ratio of first ratio term of every ratio and second ratio term of every ratio