Download Midsegments of Triangles

Classifying Polygons
Geometry
Date
Name
Essential Question: What is a polygon and how are polygons classified?
Polygon - Two-dimensional closed figure formed by three or more segments. Each
segment is called a side. Each endpoint of a side is a vertex.
To name a polygon, start with any vertex and list the vertices consecutively in a
clockwise or counterclockwise direction.
1. a) Name the polygon two different ways.
Ex. BDHKMG, BGMKHD
b) Identify the sides.
DH, HK, KM, MG, GB, BD
c) Identify the angles.
B, D, H, K, M, G
Polygons are classified by the number of its sides.
Number of Sides
3
4
5
6
7
8
9
10
11
12
...
n-gon
Name of Polygon
Triangle
Quadrilateral
Pentagon
Hexagon
Heptagon
Octagon
Enneagon
Decagon
Hendecagon
Dodecagon
Diagonal - Segment that connects two nonconsecutive vertices.
Convex Polygon - Diagonals all lie within the polygon.
Concave Polygon - At least one diagonal lies outside the polygon.
Convex Polygon
2. a) Classify the polygon by its number of sides.
Hexagon
b) Determine whether the polygon is convex or concave.
Convex
Concave Polygon
Exercises
1. Yes
2. No
3. No
4. Yes
5. Pentagon
6. Quadrilateral
7. Heptagon
8. Octagon; Concave
9. Enneagon; Convex
10. Pentagon; Concave
Reflection:
1. What is a polygon and how are they classified?