Polygons

1
Polygons

• A polygon is named based on the number of sides
  it has
• triangle, quadrilateral, pentagon, hexagon,
  heptagon, octagon, nonagon, decagon, undecagon,
  dodecagon
• A polygon with more than 12 sides is an n-gon,
  e.g., a 20-gon
• A polygon is named by listing the vertices in
  order
• Consecutive edges, vertices, and angles are the
  edges, vertices, and angles next to each other

2
Polygons

• A polygon is
• a closed figure in a plane formed by connecting
  line segments endpoint to endpoint, with each
  segment intersecting exactly two others
• Each segment is called a side of the polygon
• Each point where two segments meet is called a
  vertex of the polygon

3
Polygons

• A diagonal of a polygon is a line segment that
  connects two nonconsecutive vertices
• A polygon is convex if no diagonal lies outside
  the polygon
• A polygon is concave if at least one diagonal
  lies outside the polygon

4
Polygons

• Congruent polygons
• Two polygons are congruent if and only if the
  corresponding sides and angles are congruent
• Using if and only if means the statement is
  true in both directions
• If two polygons are congruent then the
  corresponding sides and angles are congruent
• If the corresponding sides and angles of two
  polygons are congruent then the polygons are
  congruent

CAMP       SITE
5
Polygons

• Special polygons
• Equilateral polygons have all sides congruent
• Equiangular polygons have all angles congruent
• Regular polygons are both equilateral and
  equiangular (All sides and all angles are
  congruent)