1. Basic Definitions
G.CO.1 and G.CO.12
Objectives 1, 3, 6

2. Line Segment – a portion of a line consisting of 2 points and all the points between them.
Names B c A c

3. Congruent Segments – 2 segments with the same length.P

4. Ray – a portion of a line that starts at a point and continues forever in one direction.
*Always name a ray starting with its initial point.
Names B c A c

5. Opposite Rays – 2 collinear rays with the same endpoint and going in opposite directions.B A

6. Examples 1) Name a segment. Name a ray. Name a pair of opposite rays.B C D

7. Angles - formed by 2 rays with the same endpoint.
Names B A C
Vertex – common endpoint of the two rays.

8. Classifying Angles Right Angle Acute Angle Obtuse Angle Straight Angle
= 90º between 0º and 90º
Obtuse Angle Straight Angle
Between 90º and 180º = 180º

9. Congruent Angles – angles with the same measure.
M N
A B C

10. Bisectors
Segment Bisector – divides a segment into 2 congruent segments.
Angle Bisector – divides an angle into 2 congruent angles. c A B C B A C

11. M N A B

13. Perpendicular Bisectors – a line, segment, or ray that is perpendicular (90º) and bisects a segment into 2 congruent segments.

14. Skew Lines – non-coplanar lines that are not parallel and do not intersect. Parallel Planes – planes that do not intersect.

15. Examples 2) E G C A H F D B a) Name a set of parallel lines.
b) Name a set of parallel planes.
c) Name a line that is parallel
to ABC.
d) Name a set of skew lines. E G C A H F D B

16. Examples K L B A C F D E J G I H