Definitions+for+section+9.1

Circle: The set of points in a known plane are equidistant from a given point know as the center of the circle. Radius: A segment that connects the center of a circle with a point on the circle; 1/2 the diameter. Chord: A segment whose endpoints lie on a circle. Diameter. A chord that passes through the center of a circle; twice the length of the radius of the circle. This picture shows the diameter of a circle. Arc: An unbroken part of a circle. L=M/360*C or L=M/360(2piR) Endpoints: A point at an end of a segment or the starting of a ray. Semi-circle: The arc of a circle whose endpoints are the endpointsi of a diameter. Half the circle. Minor Arc: An arc of a circle that is shorter than a semi circle of that circle. Less than 180 degrees. Major arc: An arc of a circle thats longer then a semi circle of that circle. Larger than 180 degrees. Central Angle: Is an angle formed by two rays originating from the center of a circle. Intercepted arc: An arc whose endpoints lie on the sides f an inscribed angle. Degree measure of arcs: The measure of a minor arc is the measure of its central angle. the degree measure of a major arc is 360 degree minus the degree measure of its central arc.

Arc Length: L=M/360° X(2pi*R) Chords and Arcs Theorms: In a circle, or in congruent circles, the arcs of congruent cords are half. The converse of the Chords and Arcs Theorm: In a circle or in congruent circles, the chords of congruent arcs are half the circle.