SEGMENTS, RAYS, PARALLEL LINES AND PLANESChapter 1 Section 4

SEGMENTS 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

A

B

AB or BA

NAME ALL SEGMENTS

R

TC

Q

B

P

M

N

RCRTCT

CRTRTC

QP

QB

PB

MN

NM

PQ

BQ

BP

RAYS

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

LD

The name for this ray would be LD

))))))))))))))

OPPOSITE RAYS

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

AB))))))))))))))

AD))))))))))))))

together they form AB.))))))))))))) )

PARALLEL LINES

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:

A

B

C

D

AB CD

read “segment AB is parallel to segment CD”

EXAMPLES 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!

SKEW LINES

Skew lines are lines that are not in the same plane and do not intersect

A B

CD

EF

GH

Examples of skew lines:

and AB DH

and AB CG and EF DH and EF CG and BF DC

and BF HG

SKEW LINES

Skew lines using rectangular prism

Skew lines using tissue box

Skew lines using classroom

PARALLEL PLANES

Parallel planes are planes that do not intersect In a box: top/bottom; left/right; front/back

A B

CD

EF

GH

ABCD EFGHAEHD BFGCAEFB DHGC

EXAMPLES OF PARALLEL 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