1) The document defines key geometry terms including segments, rays, parallel lines, skew lines, and planes. 2) It provides examples of how to name and identify segments, rays, parallel lines, and skew lines based on their properties. 3) Students are asked to identify parallel and skew segments, lines, and planes based on diagrams.

1. Sec. 1 – 4 Segments, Rays, Parallel Lines and Planes Objectives: 1) Identify segments and rays. 2) Recognize parallel lines.

2. Line – A series of points that extend in 2 directions without end. Notation: 2 capital letters with a line over them. Ex: Reads: Line AB A B AB

3. Segment – Is the part of a line consisting of two endpoints & all the points between them. Notation: 2 capital letters with a line over them. Ex: No arrows on the end of a line. Reads: Line segment (or segment) AB A B AB refers to the segment refers to the length of

4. Ray – Is the part of a line consisting of one endpoint & all the points of the line on one side of the endpoint. Notation: 2 capital letters with a line with an arrow on one end of it. End point always comes first. Ex: Reads: Ray AB A B AB

5. Opposite Rays – Are two collinear rays with the same endpoint. Opposite rays always form a line. Ex: Same Line Q R S RQ & RS Endpoints

6. Ex.1: Naming segments and rays. Name 3 segments: LP PQ LQ Name 4 rays: LQ QL PL LP PQ L P Q Are LP and PL opposite rays?? No, not the same endpoints Are LP and LQ different rays?? No, they the same same ray.

7. Parallel Lines – Are coplanar lines that never intersect. Coplanar – same plane Symbol [ // ] Ex: r // t Reads: line r is parallel to line t. r t

8. Skew Lines – Are noncoplanar lines that never intersect. Skew lines are never // Parallel Planes – Are planes that do not intersect. A B C D E F G H

9. What would you call two lines which do not intersect? Parallel A solid arrow placed on two lines of a diagram indicate the lines are parallel. The symbol || is used to indicate parallel lines. AB || CD

10. A slash through the parallel symbol || indicates the lines are not parallel. AB || CD

11. Skew Lines – Two lines are skew if they are not in the same plane and do not intersect. AB does not intersect CD . Since the lines are not in the same plane, they are skew lines.

12. For the rectangular box shown below, find All planes parallel to plane CDE.

13. For the rectangular box shown below, find All planes parallel to plane CDE. Plane BAH (or any plane with BAHG).

14. Parallel Lines and Transversals For the rectangular box shown below, find The intersection of plane AHE and plane CFE.

15. For the rectangular box shown below, find The intersection of plane AHE and plane CFE.

16. For the rectangular box shown below, find All segments parallel to CD.

17. Parallel Lines and Transversals AB, GH, EF For the rectangular box shown below, find All segments parallel to CD.

18. For the rectangular box shown below, find All segments that intersect CF.

19. For the rectangular box shown below, find All segments that intersect CF.

20. For the rectangular box shown below, find All lines skew to GF.

21. For the rectangular box shown below, find All lines skew to GF. Segments HE, AD, and BC are || or in the same plane. Segments GH, EF, BG and CF intersect and are in the same plane. These segments are not skew to GF.

22. 1-3 Use the figure below. Name all segments that are parallel to AE . Name all segments that are skew to AE . Parallel segments lie in the same plane, and the lines that contain them do not intersect. The three segments in the figure above that are parallel to AE are BF , CG , and DH . Skew lines are lines that do not lie in the same plane. The four lines in the figure that do not lie in the same plane as AE are BC , CD , FG , and GH .

23. Parallel to GJ? Skew to GJ? HI, DN AB, CD, CH

24. What have we learned?? Name the following line. Name a segment. Name a ray. X Y Z XY or YZ or ZX XY or YZ or XZ XY or YZ or ZX or YX

25. Parallel Lines ~ coplanar lines that do not intersect Skew Lines ~ noncoplanar They are not parallel & they do not intersect Same direction & Same plane Different direction & Different plane Lines that do not intersect may or may not be coplanar.

26. Homework- Pg. 25 # 3 – 23 , 25-33 write out sentences, 34, 44, 46 - 49

28. Don’t forget 25-33, write out sentences