Central Angle: A central angle is an angle formed by two intersecting radii such that its vertex is at the center of the circle.

Central Angle = Intercepted Arc

<AOB is a central angle. Its intercepted arc is the minor arc from A to B. m<AOB = 80º

Inscribed Angle: An inscribed angle is an angle with its vertex "on" the circle, formed by two intersecting chords.

Inscribed Angle = Intercepted Arc

<ABC is an inscribed angle. Its intercepted arc is the minor arc from A to C. m<ABC = 50º