Master the 7 pillars of school success

Common Core Standard  6.G.1 ,  6.G.3, 7.G.6
Convex Polygon
Concave Polygon
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Naming polygons game  This could be a great way to review the polygon names. The polygon game shows a shape and then asks you questions about the name or number of sides.

Naming Polygons Tips and directions for naming polygons
When you draw a line through a Concave polygon it touches the concave polygon in more that two places,but with a Convex polygon the line only touches it in two places
Concave polygons do have
internal angles greater than  180°

Convex polygons do not have any
internal angles greater than than ​180°

1. Regular Polygons have equal length sides ( congruent sides)

2. Regular Polygons have equal length angles ( congruent angles)

3. Because the measure of each central angle is congruent in regular polygons, you can find the measure of the central  angle by dividing the number of sides into 360◦
360 ÷ N (Number of sides) = Measure​ of the Central Angle of a regular polygon

# Names of Polygons

In this example the central angle equals

360/5 sides = 72 degrees
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Parallelograms

2D Polygons

## Names of Polygon Shapes

 Name Number of Sides Interior Angle Measure Central Angle Measure 360/number of sides Triangle 3 60° 120° Quadrilateral 4 90° 90° Pentagon 5 108° 72° Hexagon 6 120° 60° Heptagon or Septagon 7 128.5° 51.4° Octagon 8 135° 45° Nonagon or Enneagon 9 140° 40° Decagon 10 144° 36° Hendecagon or Undecagon 11 147.2° 32.72° Dodecagon 12 150 30° Triskaidecagon 13 152.3° 27.69° Tetrakaidecagon 14 154.2° 25.71° Pentadecagon 15 156° 24° Hexakaidecagon 16 157.5° 22.5° Heptadecagon 17 158.82° 21.17° Octakaidecagon 18 160° 20° Enneadecagon 19 161.05° 18.94° Icosagon 20 162° 18° Triacontagon 30 168° 12° Tetracontagon 40 171° 9° Pentacontagon 50 172.8° 7.2° Hexacontagon 60 174° 6° Heptacontagon 70 174.85° 5.14° Octacontagon 80 175.5° 4.5° Enneacontagon 90 176° 4° Hectagon 100 176.4° 3.6° Chiliagon 1000 176.64° .36° Myriagon 10,000 179.96° .036° n-gon n (n-2) × 180° / n You can make names using Number of sides   For example 40 Tetraconta +1 henagon +2 digon +3 trigon +4 tetragon + 5 pentagon +6 hexagon +7 heptagon + 8 octagon +9 enneagon Tetracontakaihenagon =41 sides Tetracontakaidigon =42 sides Tetracontakaitrigon = 43 sides

Central Angle
plus "Kai" for "and"
An easier and acceptable method of naming many sided polygons is as follows: 13 sided = 13-gon  17 sided =17-gon
Many of the shapes in Geometry are polygons. What is a polygon? A polygon is a two-dimensional shape that has straight lines. A polygon can have anywhere between three and an unlimited number of sides. All of the lines of a polygon connect which means there is not an opening. Each polygon is named according to it's the number of sides. Here are some examples of polygons.