What is a Vertex

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DO NOW
What is a Vertex?
Where have we seen a vertex before? How many
degrees are in a circle? Is there anything you
can tell about these four equal quadrants?
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Ms. LaCross 8th Grade Geometry Its Time to
Tessellate A Lesson in Interior Angles of
Regular Polygons
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By the end of 8th grade students should
understand
A. Geometric Properties
8th Graders should be able to
3. Understand and apply properties of polygons.
Regular polygons
Sum of measures of interior angles of a polygon
Which polygons can be used alone to generate
a tessellation and why
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NCTM Math Standards Addressed in This Lesson

• Geometry Standard
• Analyze characteristics and properties of
  geometric shapes.
• Use visualization, spatial reasoning and
  geometric modeling to solve problems
• Measurement Standard
• Apply appropriate techniques, tools and formulas
  to determine measurements

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What is a Tessellation?
A tessellation is a way to tile a floor (that
goes on forever) with shapes so that there is no
overlapping and no gaps. Visit
http//www.coolmath.com/tesspag1.htm for more
information. You will have 4 minutes to explore
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Times Up!!!!!
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Who Can Tell Me Why These are NOT Tessellations?
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Do All Shapes Tessellate? Learn the Math Behind
the Mayhem!

• Todays goals are to
• Make a tessellation
• Find out why those shapes fit together
• Reflect on what we have done!

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Vertices and Tessellations?
Create a SEMI-REGULAR Tessellation of your own
at http//nlvm.usu.edu/en/nav/frames_asid_163_g_4
_t_3.html?openactivities. Go to any vertex and
write what number-sided shapes are around it (see
below). Hypothesize why you think that pattern
Tessellates. You will have 5 minutes to do this.



Like this
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Times Up!!!!!
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Visit Cool Math http//www.coolmath.com/interior.
htm to find out more about shapes and the angles
within them fill in the chart below.
You will have 5 minutes to complete this
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Times Up!!!!!
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You should have discovered relationships like
these

Did you find the general formula to find
the measure of an interior angle of a regular
n-gon? Here It is
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Reflection Time!
Tell me about your Tessellation. What shapes
are around the vertices in your
Tessellation? What are the interior angle
measures of your shapes? Why do Tessellations
work? Are geometric shapes the only ones that
can Tessellate? Why or why not?
Hand in all work from TODAY to be GRADED!
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Grading Rubric
Scale points 2 and 4 are not explicitly
defined. These will be used to score students
who exceed one criteria, but dont quite meet the
next.