Euclid:Proposition/III/22

Proposition

In the words of Euclid:

The opposite angles of quadrilaterals in circles are equal to two right angles.

(The Elements: Book $\text{III}$: Proposition $22$)

Sources

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