Euclid:Proposition/III/20

Proposition

In the words of Euclid:

In a circle the angle at the centre is double of the angle at the circumference, when the angles have the same circumference as base.

(The Elements: Book $\text{III}$: Proposition $20$)

Sources

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