# The inscribed angle theorem

- $\alpha $ - Central angle: an angle whose apex (vertex) is the center O of a circle and whose legs (sides) are radii intersecting the circle in two distinct points A and B
- $\beta $ - Inscribed Angle: the angle formed in the interior of a circle when two chords intersect on the circle

**The inscribed angle theorem**

The measure of the central angle is equal to twice the measure of the inscribed angle subtended by the same arc $\alpha =2\beta $

A central angle has countless inscribed angles. All of them are subject to the aforementioned rule: $\alpha =2\beta $

Keywords: Central - Inscribed Angles