9.1+Chords

__Objectives-__ Define a circle and its associated parts, then use them in constructions. Get to know more about the degree measure of arcs. Learn more about the is of the length measure of arcs. Prove a theorem about chords and their intercepted arcs.

__

Circle__- A circle is the set of all points that are equidistant from a given point in the plane known as the center of the circle. The radius is the segment from the center of the circle to a point on the circle.

__Chord__- Segment whose endpoints line on a circle.

__Diameter-__ Chord that contains the center of a circle.

__Central Angle-__ Is an angle in the plane of a circle whose vertex is the center of the circle.

__Intercepted Arc-__ When the arc whose endpoints lie on the sides of the angle and whose other points lie in the interior of the angle.



__Arc-__ The unbroken part of the circle.

__Endpoints-__ Any 2 distinct points on a circle divide the circle into 2 arcs.

__Semicircle-__ Arc whose endpoints are endpoints of a diameter. Usually called a half circle because of its endpoints and another point that lies on the arc. __Minor Arc-__ Arc that is shorter than a semicircle of that circle. Just like the semicircle the minor arc is named by its endpoints.

__Major Arc-__ An arc that is longer than a semicircle of the circle. Named by its endpoints and another point that lies on the arc.

__Degree Measure Of Arcs-__ The degree measure of a minor arc is the measure of its central angle. Major arc is 360 degrees take away the degree of its minor arc. The semicircles degree measure will always be 180 degrees.

__Arc Length-__ L= M/360 degrees (2*3.14*r) L= Length r=Radius M=Degree measure of the arc.

__Chords and Arcs Theorem-__ In congruent circles or just circles, the arc of congruent chords are congruent.

__Converse Of Chords and Arcs Theorem-__ The chords of congruent arcs are 1/2.