These magnitudes are said to be corresponding^{1} (magnitudes): the leading to the leading (of two ratios), and the following to the following.
Given two ratios of positive real numbers. \[\frac\alpha\beta,\quad\frac\gamma\delta,\]
pairs of numbers \((\alpha, \gamma)\) and \((\beta,\delta)\) are called corresponding magnitudes.
Literally, "double". ↩