This document defines circle geometry terminology like chord, arc, inscribed angle, and central angle. It then presents 5 circle theorems: 1) the perpendicular bisector of a chord passes through the circle's center, 2) congruent chords are equidistant from the center, 3) the measure of a central angle is equal to twice the measure of the angle at the circumference, 4) angles subtended by the same arc are equal, and 5) an angle subtended by a diameter is a right angle. It also states that opposite angles in a cyclic quadrilateral add to 180 degrees.