1.2 Points, Line Segments, Lines and Rays

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1.2 Points, Line Segments, Lines and RaysOH MY!
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Mental Math
Solve these subtraction problems. Write your
answer on your slate. 9 0 12 6 16 9
17 8 90 40 140 70
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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.
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Reviewing Points, Line Segments, Lines and Rays
When you connect two points using a straightedge,
you create a line segment
A
B
points
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Points, Endpoints and Line Segments
endpoint
endpoint
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?

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Stop and Chat!
endpoint
endpoint
A
B
How 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
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Lines
point
point
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

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Stop and Chat!
point
point
A
B
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
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Ray
endpoint
point
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

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Stop, Try and Chat!
endpoint
point
C
D
Short way to write the name is CD
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
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Lets 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?
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Independent work MJ page 4
You can use SRB pages 90 and 91 to help you!
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Wrap it UP!

• In your Math Notebook
• Draw and label YX
• Draw and label HG
• Draw and label VB

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Addition Top-It
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Tonights Homework
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Math Boxes