1. Warm Up: Investigating the Properties of Quadrilaterals Make a conjecture about the sum of the interior angles of quadrilaterals. You may use any material/equipment to help test your conjecture. Be prepared to justify your conclusion with the data you collect. You may choose to work as a group or by yourself.

2. Interior Angles of a Quadrilateral The sum of the measures of the interior angles of a quadrilateral is 360 0. m  1 + m  2 + m  3 + m  4 = 360 0 1 2 3 4

3. Chapter 6.1: Polygons Students will identify regular and nonregular polygons. Students will describe characteristics of a quadrilateral.

4. What’s a Polygon? A plane figure that meets the following conditions… 1.It is formed by three or more segments called sides, such that no two sides with a common endpoint are collinear. 2.Each side intersects exactly two other sides, one at each endpoint.

5. More Vocabulary Vertex (vertices): each end point of a side of a polygon Name vertices of a polygon consecutively. State whether each figure is a polygon. If not, explain why. A B C D E F

6. Convex polygon: a polygon such that no line containing a side of the polygon contains a point in the interior of the polygon. Every internal angle is less than or equal to 180 o. Concave or Nonconvex polygon: a polygon that is not convex. Always has an interior angle with a measure that is greater than 180 o. Now draw your own example of a concave and convex polygon.

7. Concave Convex

8. Equilateral: a polygon with all sides congruent Equiangular: a polygon with all of its interior angles congruent Regular: a polygon that is equilateral and equiangular Diagonal: a segment in a polygon that joins two nonconsecutive vertices.

9. Cool Down: Find the missing values. 1. 2.