1. Chapter 1-6 (Classify Polygons)  What is a polygon?  A closed plane figure formed by 3 or more line segments, with no two sides being collinear.

2. Chapter 1-6 (Classify Polygons)  Two types of polygons  Convex: All vertices going outward  Concave: A vertex going inside the polygon

3. Chapter 1-6 (Classify Polygons)  Example  Tell whether the following polygons are convex or concave

4. Chapter 1-6 (Classify Polygons)  How do you classify polygons?  Congruent polygons:  Named by the number of sides  After 12 sides, the general name is a n-gon, where n is the number of sides  Equilateral: All sides are congruent  Equiangular: All angles are congruent  Regular: Convex polygon that is both

5. Chapter 1-6 (Classify Polygons)  Example  Classify the polygons by the number of sides. Is it equilateral, equiangular, or regular?

6. Chapter 1-6 (Classify Polygons)  Example

7. Chapter 1-6 (Classify Polygons)  Example  The expression (4x + 8)º and (5x – 5)º represent the measures of 2 of the congruent angles in the previous problem. Find the measure the an angle.