1. Lesson 8-1: Circle Terminology
Bell Ringer
Lesson 8-1: Circle Terminology

2. Lesson 8-1: Circle Terminology
11.1
Parts of a Circle
Lesson 8-1: Circle Terminology

3. Lesson 8-1: Circle Terminology
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
Lesson 8-1: Circle Terminology

4. Lesson 8-1: Circle Terminology
Definitions
Chord :
The segment whose endpoints lie on the circle.
Diameter :
A chord that contains the center of the circle.
Tangent :
A line in the plane of the circle that intersects the circle in exactly one point.
Tangent
Point of Tangency :
Chord
The point where the tangent line intersects the circle.
Diameter
Secant :
A line that contains a chord.
Secant
Lesson 8-1: Circle Terminology

5. Lesson 8-1: Circle Terminology
Example: In the following figure identify the chords, radii, and diameters.
Chords: O D A B F C E
Radii:
Diameter:
Lesson 8-1: Circle Terminology

6. Lesson 8-1: Circle Terminology
Definitions
Congruent Circles :
Circles that have congruent radii. 2 2
Concentric circles :
Circles that lie in the same plane and have the same center.
Lesson 8-1: Circle Terminology

7. Lesson 8-1: Circle Terminology
Homework
Pg. 591 #
Lesson 8-1: Circle Terminology