For, since A is greater than C, and B is another, chance, magnitude,
therefore A has to B a greater ratio than C has to B. [V. 8]
But, as A is to B, so is C to D;
therefore C has also to D a greater ratio than C has to B. [V. 13]
But that to which the same has a greater ratio is less; [V. 10]
therefore D is less than B;
so that B is greater than D.