1. Lesson 1-6: Classify Polygons

2. Polygon A polygon is a closed figure with the following properties It is formed by three or more line segments called sides Each side intersects exactly two sides

3. Examples of Polygons A BC Z M Y W X J HL IK A B C DE F GHKL L M N O Non-examples of polygons:

4. Concave or Convex Polygons can be concave or convex. Convex Concave

5. # of sidesPolygon 3Triangle 4Quadrilateral 5Pentagon 6Hexagon 7Heptagon 8Octagon 9Nonagon 10Decagon 12Dodecagon nN-gon Polygons can be classified by the number of sides they have. On page 43 of your text book

6. In an equilateral polygon all sides are congruent. In a equiangular polygon all angles are congruent.

7. Regular Polygons A convex polygon in which all sides are congruent and all angles are congruent is called a regular polygon. Think about it… Can you tell me another name for a regular triangle? Regular quadrilateral??

8. Example #1 Name each polygon by the number of sides. Then classify it as convex or concave. a) b)

9. Example #2 Name each polygon by the number of sides, classify it as convex or concave, and classify it as equilateral, equiangular, regular. a) b)

10. Tell whether the statement is always, sometimes, or never true. A regular pentagon is concave. A pentagon is regular A square is a regular polygon A triangle is equilateral but not equiangular.

11. Draw a figure that fits the description A triangle that is not regular A convex hexagon An equiangular octagon that is not equiangular

12. Each figure is a regular polygon. Expressions are given for two side lengths. Find the value of x. x + 7 2x - 3 -7x - 8 5x - 32

13. Each figure is a regular polygon. Expressions are given for two side lengths. Find the value of x. x² + 5x - 7 x² - x + 5

14. The lengths (in meters) of two sides of a regular heptagon are represented by the expressions 11x – 32 and 6x -7. Find the length of a side of the heptagon.

15. Homework!! Pgs 44 – 46 #8 - 30