Lesson 8-1: Lesson 8-1: Circle Terminology 1 Lesson 8-1 Circle Terminology
Circle Definition: Lesson 8-1: Circle Terminology 2 Circle Definition Circle : The set of points coplanar points equidistant from a given point. The given point is called the CENTER of the circle. The distance from the center to the circle is called the RADIUS . Center Radius
Definitions: Lesson 8-1: Circle Terminology 3 Definitions Chord : The segment whose endpoints lie on the circle. Chord Diameter : A chord that contains the center of the circle. Diameter Secant : A line that contains a chord. Secant Tangent : A line in the plane of the circle that intersects the circle in exactly one point. Point of Tangency : The point where the tangent line intersects the circle. Tangent
Example: In the following figure identify the chords, radii, and diameters.: Lesson 8-1: Circle Terminology 4 Example: In the following figure identify the chords, radii, and diameters. Chords: Radii: Diameter: O D A B F C E
Slide 5: Lesson 8-1: Circle Terminology 5 Circles that have congruent radii. 2 2 Circles that lie in the same plane and have the same center. Definitions Concentric circles : Congruent Circles :
Polygons: Lesson 8-1: Circle Terminology 6 Polygons A polygon inside the circle whose vertices lie on the circle . Inscribed Polygon: Circumscribed Polygon : A polygon whose sides are tangent to a circle .
ARCS: Lesson 8-1: Circle Terminology 7 ARCS The part or portion on the circle from some point B to C is called an arc . A B C Arcs : Semicircle: An arc that is equal to 180°. Example: O A B C Example:
Minor Arc & Major Arc: Lesson 8-1: Circle Terminology 8 Minor Arc & Major Arc Minor Arc : A minor arc is an arc that is less than 180° A minor arc is named using its endpoints with an “arc” above. A B Example: Major Arc: A major arc is an arc that is greater than 180°. A major arc is named using its endpoints along with another point on the arc (in order). A B C Example: O
Example: ARCS: Lesson 8-1: Circle Terminology 9 Example: ARCS Identify a minor arc, a major arc, and a semicircle, given that is a diameter. A C D E F Minor Arc: Major Arc: Semicircle: