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