1. 3.4 Polygons (2 cards)

2. Polygons

3. Naming Polygons  Name the Polygon  Name the Vertices  Name the Sides  Name the Angles

4. Naming Polygons  Name the Polygon ABCDE or DCBAE  Name the Vertices A, B, C, D, E  Name the Sides AB, BC, CD, DE, EA  Name the Angles

5. Classifying Polygons 3 Triangle 4 Quadrilateral 5 Pentagon 6 Hexagon 7 Heptagon 8 Octagon 9 Nonagon 10 Decagon 11 11-gon 12 Dodecagon n- gon

6. Classifying Polygons Convex _________Concave ________

7. Classifying Polygons Convex HexagonConcave Heptagon

8. Polygon Angle-Sum Theorem The sum of the interior angles is: (n – 2)180 Where n is the number of sides See Sketchpad

9. Find the sum of the measure of the angles of a 13-gon ( 13 – 2 ) 180 (11) 180 1980 degrees

10. Find the measure of the missing angle  First find the total degrees: (5-2)180 540  Write an equation 117+100+105+115+y=540  Solve 437 + y = 540 y = 103

11. Polygon Exterior Angle-Sum Theorem The sum of the measures of the exterior angles of a polygon, one at each vertex, is 360 See Sketchpad

12. Definitions  Equilateral Polygon All Sides congruent  Equiangular Polygon All Angles congruent  Regular Polygon All Sides and Angles congruent

13. The measure of an exterior angle of a regular polygon is 36 degrees. Find the measure of an interior angle and the number of sides of the polygon

14.  Consider the polygon. What do you notice about the interior and exterior angles?  They are supplementary The measure of an exterior angle of a regular polygon is 36 degrees. Find the measure of an interior angle and the number of sides of the polygon

15. The sum of an exterior angle and an interior angle is 180. 36 + y = 180 y = 144 The Interior angle measures 144 degrees

16. The measure of an exterior angle of a regular polygon is 36 degrees. Find the measure of an interior angle and the number of sides of the polygon  Regular Polygon  All angles are congruent  Total exterior angles is always 360  360 divided by the angle measure will give the number of sides  360/36 = 10  10 Sides

17. Homework  3-4 Pg 147