Unit 2 Geometry Attributes and Properties of Polygons

• A polygon is a closed plane figure formed by three or more segments that intersect only at their points
• A triangle has 3 sides
• A quadrilateral has 4 sides
• A pentagon has 5 sides
• A hexagon has 6 sides
• a Heptagon has 7 sides
• An Octagon has 8 sides
• A nonagon has 9 sides
• A decagon has 10 sides
• a Dodecagon has 12 sides
• an n-gon has n sides
• Closed straight sides

  
• Closed straight sides

  
• Curved sides

  Only 2 sides

  
• opening, not a complete shape

  
• A regular polygon is a polygon that is both equilateral and equiangular
• An irregular Polygon is not an equilateral or equiangular
• Concave Polygon is if any part of a diagonal contains points in the exterior of a polygon

  
• A convex polygon is if no diagonal contains points in the exterior than it is convex

  
• The sum of all interior angles of a polygon with n sides is (n-2)180 degrees.
• same angles and sides

  
• diagonal contains points in the exterior

  
• Vertex is a common endpoint between two sides

  
• A diagonal is a segment connecting 2 non-consecutive vertices

  
• A regular polygon is always convex
• Non consecutive means vertices not right next to each other
• A radius is a segment connecting the center to a vertex

  
• A central angle is an angle created by 2 consecutive radii

  
• an Apothem is a perpendicular segment from the center of the polygon

  
• Inscribed is when a polygons vertices lie on a circle (or another polygon) “The hexagon is inscribed in the circle”

  Remember as “inside”
• Circumscribe is when a circle is on the outside of another polygon. “The circle circumscribed the hexagon.“

  Remember as “outside”
• To find the measure of each interior angle of a regular 16-gon you do (16-2)180 which equals 2520 and divide it by the number of sides which is 16 so the answer is 157.5