Definition:Euclid's Definitions - Book VII/20 - Proportional

Definition

In the words of Euclid:

Numbers are proportional when the first is the same multiple, or the same part, or the same parts, of the second that the third is of the fourth.

(The Elements: Book $\text{VII}$: Definition $20$)

Sources

• 1926: Sir Thomas L. Heath: Euclid: The Thirteen Books of The Elements: Volume 2 (2nd ed.) ... (previous) ... (next): Book $\text{VII}$. Definitions