smde313

=Chapter 9=

Objectives:
Define and use the degree measure of arcs. Define and use the measure of arcs Prove a theorem about chords and their intercepted arcs.__**
 * __Define a circle and its associated parts and use them in constuctions

__Blue Boxes__:

 * Circle:** A circle is the set of all points in a plane that are equidistant from a given point in the plane know as the center of a circle.


 * Radius:** (plural:radii) is a segment from the center of the circle to a point on the circle.


 * Chord:** is a segment whose endpoint line on a circle.


 * Diameter:** is a chord that contains the center of a circle.


 * Semicircle:** is an arc whose endpoints are endpoints of a diameter. A semicircle is informally called a half-circle. a semicircle is named by its endpoints and another point that lies on the arc.


 * Central angle:** of a circle is an angle in the plane of a circle whose vertex is the center of the circle.


 * Interceptered arc:** whose endpoints lie on the sides of the angle and whose other points lie in the inteerior of the angle.


 * Degree Measure of Arcs:** The degree measure of a minor arc is the measure of its central angle.The degree measure of a arc is 360 degrees minus the degree measure of its arc. The degree measure of a semicircle is 180 degrees.


 * Arc Length:** If R is the radius of a circle and M is the degree measure of an arc of the circle, then the length, L, of the arc is given by the following: L=M/360(2piR)


 * Chords and Arcs Theorem:** In the circle, or in congruent circles, the arcs of congruent chords are similar.