S EGMENTS, R AYS, P ARALLEL L INES AND P LANES Chapter 1 Section 4

S EGMENTS A segment is an infinite collection of points with a definite beginning and end (called endpoints) Segments are named using the endpoints of each segments with a bar (or segment) over them Only 2 points are used to name segments or

N AME ALL SEGMENTS

R AYS A ray is a collection of points with one endpoint that extends in one direction without end A ray is named using 2 points To name a ray we start at the endpoint and go towards the arrow The symbol for ray is an arrow over both points, pointing to the right L D The name for this ray would be

O PPOSITE R AYS Rays that start at the same endpoint and go in exact opposite directions Opposite rays always form a line A B D and are opposite rays together they form

P ARALLEL L INES Parallel lines are lines in the same plane that do not intersect Lines that are an equal distance apart at every point Symbol for parallel: read “segment AB is parallel to segment CD”

E XAMPLES OF PARALLEL LINES Parallel lines in the classroom Rails holding up ceiling tiles Sides of the board Top/bottom of the board Grout lines in the cinderblocks Frame of the door Parallel lines in 3 dimensions Using rectangular prism Using tissue box Using classroom Diagonals!

S KEW LINES Skew lines are lines that are not in the same plane and do not intersect A B C D E F G H Examples of skew lines:

S KEW LINES Skew lines using rectangular prism Skew lines using tissue box Skew lines using classroom

P ARALLEL PLANES Parallel planes are planes that do not intersect In a box: top/bottom; left/right; front/back A B C D E F G H

E XAMPLES OF P ARALLEL PLANES Using rectangular prism Using tissue box Using classroom

Classwork: Selected problems from: p. 25 – 26 #1 – 3, 4, 6 – 8, 10 – 12, 14, 16 – 23, 25 – 33 Homework: WS 1.4