Warm Up

1
Warm Up

• A complement of an angle is five times as large
  as the angle. Find the angles.
• The measure of one of two complementary angles is
  six less than twice the measure of the other.
  Find the angles.

2
Classifying Polygons

• Objective
• Students will identify and name polygons.
  Perimeter of polygons will also be found.

3
Polygons

• A polygon is a closed figure formed by coplanar
  segments such that
• The sides that have a common endpoint are NOT
  collinear
• Each side intersects exactly 2 other sides, but
  ONLY at their endpoint
• A polygon is named by the letters of its vertices
  written in CONSECUTIVE order.

4
Convex or Concave?

• Convex polygons have no points of the lines in
  the interior of the figure.

• Concave polygons have some of the lines passing
  through the interior of the figure.

5
Regular or Irregular?

• A convex polygon in which all the sides are
  congruent and all the angles are congruent is a
  regular polygon.
• Otherwise, the polygon is irregular.

6
Names of Polygons
Number of Sides Polygon Name
3 Triangle
4 Quadrilateral
5 Pentagon
6 Hexagon
7 Heptagon
8 Octagon
9 Nonagon
10 Decagon
12 Dodecagon
n N-gon
7
Perimeter

• The perimeter of a polygon is the sum of the
  lengths of its sides.
• Find the perimeter
• Find x

8
Classify the polygon

• Name the polygon by its number of sides. Then
  classify it as convex or concave and regular or
  irregular.