# Section 1 4 Segments Rays Parallel Lines and

• Slides: 13

Section 1. 4 Segments, Rays, Parallel Lines, and Planes

1 -4 Segments, Rays, Parallel Lines, and Planes Objectives / “I can…” n Define line segments and rays n Properly name line segments and rays n Identify parallel lines and skew lines

Ch 1 -4: Segments, Rays, Parallel Lines & Planes Line Segment • is part of a line that has a beginning and an end (called endpoints). • named using both endpoints and w/ a little segment on top A B AB or BA

Ray • Is part of a line that has a specific starting point and goes forever in one direction. • Name a ray starting with the endpoint. (The 2 nd letter tells which direction to go. ) • Put a small ray symbol over the letters. DE or D E F DF

Rays, continued B A AB B A n Are these two rays the same? No • Different endpoints • Extend in different directions BA

Opposite Rays • are 2 collinear rays with the same endpoint. • they form a line R O B I BR & BN are opp. rays N

Lines that do not intersect may or may not be coplanar. 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

Hint: Parallel lines – same direction same plane Skew Lines – different direction different plane

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

Parallel Planes n Parallel planes are planes that never intersect n n Example: the purple planes in the above illustration A line and plane that never intersect are also parallel

Quick Check