1. Plane Geometry Unit 7 - Quadrilaterals Section 1.6 – Classify Polygons Day 1

2. WARM-UP Grab a worksheet from the front table and complete it.

3. What can we classify the object that the individual is standing on? PLANE

4. What exactly is a plane? PLANE – 2 dimensional object that extends infinitely in two directions.

5. What happens if I cut a shape out of a plane? We have now created a polygon.

6. Okay, so what is a polygon? Polygon – closed plane figure with the following two properties: 1)It is formed by three or more line segments, a.k.a. the sides. 2)Each side intersects exactly two sides, one at each endpoint, so that no two sides with a common endpoint are collinear.

7. What are the parts of a polygon? How do I label it? Sides and Vertices (plural of vertex) are the parts. List the vertices in consecutive order. Vertex Side DC B A E Label: Pentagon ABCDE or Pentagon CBAED

8. Convex vs Concave? Convex – no line that contains a side of the polygon contains a point in the interior of the polygon. Concave – line contains a point in the interior. Convex Concave Point in the interior Interior

9. How do we classify? Number of Sides Types of Polygon Number of Sides Types of Polygon 3Triangle8Octagon 4Quadrilateral9Nonagon 5Pentagon10Decagon 6Hexagon12Dodecagon 7HeptagonnN-gon 3 By the number of sides:

10. Are there special types of polygons? Yes, but only for convex polygons:  Equilateral – all the sides are congruent  Equiangular – all the angles are congruent  Regular – convex polygon that is both equilateral and equiangular

11. 1.6 Answers 1.No, curved edges 2.Yes, Concave 3.Yes, Convex 4.Pentagon, Regular 5.Quadrilateral, Equilateral 6.Triangle 7.Hexagon 8.8x – 6 = 4x + 22 4x = 28 x = 7 50 feet 9.3x + 63 = 7x – 45 -4x = -108 x = 27 144 o

12. 1.6 Answers 10.-2x + 41 = 7x - 40 -9x = -81 x = 9 23 km 15.Images Vary 16.Images Vary 17.Images Vary 18.Images Vary 19.2x = x + 30 x = 30 20.3x + 32 = 13x + 27 10x = 5 x = ½ 21.x 2 – 12 = 2x 2 – 61 x 2 = 49 x = 7