We started the class by reviewing out chapter 9 tests.

After we began a new chapter (chapter 10) Polygons.

Convex Polygons

No continuation of any side

which passes through the inside the polygon is convex

Concave Polygons

If the continuation of one side passes inside the polygon it is concave.

Classification of polygons

n/ Name

3/ Triangle

4/ Quadrilateral

5/ Pentagon

6 /Hexagon

7 /Heptagon

8/Octogon

9 /Nonagon

10 /Decagon

12 /Docecagon

any # /n-gon

Regular Polygons

Polygons with all sides and angles congruent.

Diagonal: A segmant connecting two non ajascent vertices.

Triangle=180 degrees

Hexagon= 720 degrees

Pentagon= 540 degrees

Quadrilateral= 360 degrees

Theorem 10-1: Interior Angle sum

n=number of sides

Si= Sum of interior angle

Si= 180 (n-2)

Theorem 10-2: Exterior angle sum

Se= 360 degrees

Exterior Angle:

3(180) = Si + Se

3 x 180 = 180 (3-2) + Se

Se= 360 degrees

4 (180) = Si + Se

4 x 180= 180 (4-2) + Se

Se = 360 degrees

Poygons

Si= 180 (n-2)

Se= 360 degrees

i + e angles = 180 degrees

Regular Polygons

i = Si/n

e=360/n