Polygons Classify.doc 1 revised:10/13/2006

Geometry

Polygons Classifying them!

First a few definitions; a Polygon is defined as a two-dimensional figure made up of non-intersecting line segments connected end to end. Can you identify the Polygons from the figures below?

These are POLYGONS These are NOT POLYGONS

Polygon Parts & Generally accepted Names

Side - one of the line segments that make up the polygon.

Vertex - point where two sides meet. Two or more of these points

are called vertices.

Diagonal - a line connecting two vertices that isn't a side.

Interior Angle - Angle formed by two adjacent sides inside the

polygon.

Exterior Angle - Angle formed by two adjacent sides outside the

polygon.

Name of Polygon Number of Sides Name of Polygon Number

of Sides Triangle 3 Octagon 8

Quadrilateral 4 Nonagon 9 Pentagon 5 Decagon 10 Hexagon 6 Dodecagon 12 Heptagon 7 n-gon n

Polygons Classify.doc 2 revised:10/13/2006

Polygon Relationships Here is a graphic organizer that should help you classify polygons by their characteristics. Complete the NAMES in each polygon and make marks of CONGRUNCE or where a RIGHT ANGLE exists to help show the properties of the Polygon.

Polygons

Triangles Quadrilaterals

No Sides Parallel

One pair of Parallel

sides

Both sets of sides are

parallel

Polygons Classify.doc 3 revised:10/13/2006

EXTEND and go farther… Other Polygon Relationships

Here is a table listing the prefixes and suffixes that are suggested to name polygons. Try looking at the list and naming a polygon with more than 10 sides. First look a a few examples.

Polygon Names These are names for other polygons that have been proposed.

Sides Name Sides Name 9 Nonagon, Enneagon 30 Triacontagon

11 Undecagon, Hendecagon 40 Tetracontagon 13 Tridecagon, Triskaidecagon 50 Pentacontagon 14 Tetradecagon, Tetrakaidecagon 60 Hexacontagon 15 Pentadecagon, Pentakaidecagon 70 Heptacontagon 16 Hexadecagon, Hexakaidecagon 80 Octacontagon 17 Heptadecagon, Heptakaidecagon 90 Enneacontagon 18 Octadecagon, Octakaidecagon 100 Hectogon, Hecatontagon 19 Enneadecagon, Enneakaidecagon 1,000 Chiliagon 20 Icosagon 10,000 Myriagon

To construct a name, combine the prefix + suffix

Sides Prefix 20 Icosikai... 30 Triacontakai... 40 Tetracontakai... 50 Pentacontakai... 60 Hexacontakai... 70 Heptacontakai... 80 Octacontakai... 90 Enneacontakai...

+

Sides Suffix +1 ...henagon +2 ...digon +3 ...trigon +4 ...tetragon +5 ...pentagon +6 ...hexagon +7 ...heptagon +8 ...octagon +9 ...enneagon

Here’s Two Examples: 46 sided polygon - Tetracontakaihexagon 28 sided polygon - Icosikaioctagon

Try some: Instead of saying an N-gon with 46 sides, or using a 46-gon, try to come up with it’s name.

1. Name a 34 sided polygon 2. Name a 67 sided polygon