1.2 points, line segments, lines and rays…oh my!

1.2 Points, Line Segments, Lines and

Rays…OH MY!

Mental Math

Solve these subtraction problems.

Write your answer on your slate.

9 – 0 =

12 – 6 =

16 – 9 =

17 – 8 =

90 – 40 =

140 – 70 =

Math Message

Read SRB pages 88 and 89.

In your Math Notebook, please list three places where geometry can be found in our

world.

Be ready to share.

Reviewing Points, Line Segments, Lines and Rays

A B

points

When you connect two

points using a straightedge, you

create a

line segment

Points, Endpoints and Line Segments

A B

line segment• letters are often used to name a line segment

• ONE name for this line segment is “line segment AB”

• A short way to write “line segment AB” is AB

• Another name for this line segment is “line segment BA”

• What is the short way to write “line segment BA?”

endpoint

endpoint

Stop and Chat!

A BHow would you describe a line segment

to someone who has never seen one before?

What are some examples of line segments that we can find in the world?

EXAMPLE: part of a spider web

endpoint

endpoint

Lines

A B

lines• extending line segment AB in both directions and drawing an arrowhead at each end makes a LINE

• This line is called “line AB” or “line BA”

• A short way to write the names of these lines is

AB or BA

point point

Stop and Chat!

A B

point point

How is a line different from a line segment?

What are some examples of lines that we can find in the world?

EXAMPLE: The horizon in a landscape

Ray

C D

rays• line segment that goes on without end in only ONE

direction

• Point C is the ENDPOINT of the ray CD

• The letter that names the ENDPOINT is ALWAYS

written first.

Short way to write the name is CD

endpoint

point

Stop, Try and Chat!

C D

On your slate, draw ray ZY. Remember that the endpoint of the ray is ALWAYS

written first.

What are some examples of lines that we can find in the world?

Example: Hitting a golf ball

endpoint

point

Short way to write the name is CD

Let’s Review!Is it ever possible to draw all of a line?

All of a line segment? All of a ray?

How many line segments can you name using the points marked on this line?

How many rays can you name?

Independent work MJ page 4

You can use SRB pages

90 and 91 to help you!

Wrap it UP!

In your Math Notebook…

Draw and label YX

Draw and label HG

Draw and label VB

Addition Top-It

Tonight’s Homework

Math Boxes