2. Happy Thursday! Do Now:
Recall that a complete rotation around a point is 360°. Find the angle measure represented by each letter (x, y, and z).

3. What is a Polygon?
Polygon: “A closed figure in a plane, formed by connecting line segments endpoint to endpoint with each segment intersecting exactly two others.”
Each line segment id called a side of the polygon
Each endpoint where the sides meet is called a vertex of the polygon.

4. Names of Polygons
Sides
Name 3
Triangle 4
Quadrilateral 5
Pentagon 6
Hexagon 7
Heptagon 8
Octagon 9
Nonagon 10
Decagon 11
Undecagon 12
Dodecagon n
n-gon
Polygons are classified by the number of sides it has:

5. Naming Polygons
To name a polygon, start at any vertex, and list the vertices in consecutive order:
Observe the special notation for triangles (why?)

6. Consecutive Things
Consecutive Angles: Angles that share a common side.
Consecutive Vertices: Vertices that share a common side
Consecutive Sides: Sides that share a common vertex.

7. Diagonals
A diagonal of a polygon is a line segment that connects two nonconsecutive vertices.
Convex Polygons
Concave Polygons
A polygon is convex if no diagonal is outside the polygon
A polygon is concave if at least one diagonal is outside the polygon

8. “Equi” Polygons Equilateral Polygon: Equiangular Polygon:
All sides have equal length.
Equiangular Polygon:
All angles have equal measurements
Regular Polygon:
Polygon that is both equilateral and equiangular

9. Practice
Draw the odd regular polygons from 3 to 11!

10. Review (Quiz Tomorrow!)
Name a pair of complementary angles and a pair of vertical angle in the figure to the left.
Is it possible for four lines in a plane to intersect in exactly zero points? 1 pt? 2 pts? 3 pts? 4 pts? 5 pts? 6 pts? Draw sketches to support your answers.

11. Review (Quiz Tomorrow!)