Given two points A and B, lines from them to center of the circle form the central angle∠AOB. The central angle is the smaller of the two at the center. It does not mean the reflex angle ∠AOB. As you drag the points above, the angle will change to reflect this as it increases through 180°.
Identify the inscribed angle and central angle subtended by the same arc. Recognize that the central angle is twice the measure of the inscribed angle subtended by the same arc. Identify the tangent(s) to acircle. Identify the point of tangency on a circle