1. Geometry 6-1 Properties of Polygons
Polygon: multi-sided shaped.
Traits: straight lines, lines don’t cross, closed
Polygons
Not Polygons

2. Parts of a Polygon
Diagonal: segment that connects two nonconsecutive vertices

3. Names of Polygons

4. Definitions Convex: all diagonals are inside the shape.
Concave: at least one diagonal goes outside the shape.
Regular polygon: a polygon that is convex, equilateral, and equiangular
A polygon that is not regular is irregular

5. Tell whether the follow polygons are regular/irregular and concave/convex.
irregular, convex
regular, convex

6. irregular, concave
regular, convex

7. Geometry 6-1 Interior and Exterior Angles of Polygons
Draw the following shapes:
Triangle
Rectangle (Quadrilateral)
Pentagon
Hexagon
Octagon
Draw all possible diagonals from one of the vertices.

8. Table n (# of sides) # of Triangles Sum of Interior Angles 3 4 5 6 7 8

9. Table n (# of sides) # of Triangles Sum of Interior Angles 3 1 180° 42
360° 5
540° 6
720° 7
900° 8
1080° n
(n - 2)
(n – 2) x 180°

10. Example Find the sum of each interior angle of a regular 25-gon.
(25 – 2) x 180 = 4140° for all 25 angles
4140° / 25 = 165.6° for each angle

11. Measure of Exterior Angles
The sum of the exterior angles of a convex polygon is always 360°.
Example:
Find the measure of each exterior angle of a regular hexagon.
360° / 6 = 60° for each exterior angle