Chapter 10 Geometric Figures

§ 10.2 Polygons and Tessellations

• Angles in Polygons
  • Interior angles, aka vertex angle
  • Notation
  • Sum of Interior angles
  • The sum of the interior angles of any triangle is 180 degrees
    
    
  • Activity: Find a formula for the sum of the interior angles of an n-gon.
• Congruence
  • Congruent line segments
  • Congruent angles
  • Congruent plane figures
• Regular Polygons
  • Equilteral Triangle
  • Square
  • Others
• Polygon Angles
  • Internal, aka vertex
  • External
  • Central
• Drawing Regular Polygons
  • Method 1: Line segments and angles repeated
  • Method 2: Inscribe in circle from central angle
  • Try on paper if a protractor is available
  • Try in Geogebra, geometry version
    or maybe Geogebra, classic version
• Tesselations
  • Regular
    
  • Semiregular
    
  • Other types:
    • Euclidean_tilings_by_convex_regular_polygons
    • Aperiodic_tiling