An Introduction to:

1. An Introduction to: Geometry By Wendy Bacon

2. Terms and Definitions . . .

3. Plane P • A flat surface • Continues infinitely in all directions • Labeled with a Capital Letter • Example: Plane P

4. • D Point • A position in a plane • Labeled with a Capital Letter • Example: Point D

5. • B • A • Example: AB Line • A straight path of points • Continues infinitely in both directions • Can be determined by any two of its points • Named by any two of its points

6. D C • Example: CD Line • Part of a line • Has two endpoints • Named by the two endpoints Segment

7. G F • Example: FG Ray • Part of a line • Has one endpoint • Continues infinitely in the other direction • Named by the endpoint and one other point

8. I J K Angle • Formed by two rays with a common endpoint • Named by any three points • One point from one ray • The common endpoint • One point from the other ray • The common endpoint must be named in the middle • Example: < IJK

9. I J K Vertex • The end point of an angle • The middle point of the angle name • This vertex is Point J

10. • R • • • M L N • Q • MN and QR intersect at Point L Intersecting Lines • Meet at a point

11. W • WX YZ Y Z X Perpendicular Lines • Intersect to from right angle

12. Example: QR | | ST Parallel Lines • Must be in the same plane • Never intersect • Are the same distance apart at all points S T Q R

13. J N K M L Polygon • A closed figure • Lies within a plane • Sides are made up of line segments • Named by its vertices in the order that they appear • Example: Polygon JKLMN

14. Q R V S U T Polygon • A closed figure • Lies within a plane • Sides are made up of line segments • Named by its vertices in the order that they appear • Example: Polygon QRSTUV

15. Q R J N K V S M L U T Polygon Polygon • A closed figure • Lies within a plane • Sides are made up of line segments • Named by its vertices in the order that they appear • Example: Polygon JKLMN • Example: Polygon QRSTUV