An inscribed angle is an angle made up of two secant lines of a circle intersect at a point on the circle.
In the figure shown, is the inscribed angle.
One basic property of an inscribed angle is that the intercepted arc of the angle has exactly twice the measure of the inscribed angle. In the figure above, , so .
Another way to state this is that the measure of the inscribed angle is half the measure of the intercepted arc.