M316L Chapter 9 Section 9.2: Symmetry and Tessellations

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M316L Chapter 9Section 9.2 Symmetry and
Tessellations

• Instructor Ricardo Teixeira
• October 1st, 2007

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Symmetry

• Give examples of symmetries in real life
• Describe the symmetries on the figures

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Reflection and rotation symmetry

• Create a figure with reflection symmetry
• Create a different one, this time with rotation
  symmetry
• Symmetries in triangles, quadrilaterals, polygons

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What kind of symmetries?

• Look at the figure and tell all symmetries you
  see.

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Letter symmetries

• Some letters have symmetry

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Symmetry breaking

• Discuss this term
• Example

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In Spaceland

• What would be symmetries in 3D figures?
• Line of symmetry and plane of symmetry
• What are the symmetries here?

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Tessellations

• Examples

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Tessellations

• Try to define it
• Which figures tessellate?
• Which triangles tessellate?
• Which regular polygons?

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Combination of polygons

• What is the wanted condition to even consider a
  tessellation of a combination of polygons?
• Example

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More examples

• Trapezoids
• Other irregular polygon

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Figure 9.39
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Figure 9.39
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Figure 9.39