Inscribed angle (constructions)

Given a circle with center $O$, an inscribed angle is formed by two chords $AB$ and $AC$ that meet at a point $A$ on the circle. The angle $BAC$ is called the inscribed angle subtended by arc $BC$.

Important properties

• The measure of an inscribed angle is half the measure of the central angle subtending the same arc.

• All inscribed angles subtending the same arc are equal.

• An inscribed angle subtending a semicircle (diameter) is a right angle.