Definition:Euclid's Definitions - Book I/15 - Circle

Definition

In the words of Euclid:

A circle is a plane figure contained by one line such that all the straight lines falling upon it from one point among those lying within the figure are equal to one another;

(The Elements: Book $\text{I}$: Definition $15$)

Sources

• 1926: Sir Thomas L. Heath: Euclid: The Thirteen Books of The Elements: Volume 1 (2nd ed.) ... (previous) ... (next): Book $\text{I}$. Definitions