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

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

Congruent Segments – 2 segments with the same length. P

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

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

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

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

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

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

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

  M N A B

 

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

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

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

Examples K L B A   C F D E J G I H