Definition

Definition Polygon

A polygon is a plane figure that is formed by three or more segments called sides, such that no two sides with a common endpoint are collinear, and each side intersects exactly two other sides, one at each endpoint. Each endpoint is called a vertex of the polygon

Examples of Polygons

1.6 Classify Polygons

No: All sides must be straight

Yes

No: All sides must be straight

Names

Names Polygon Names

A polygons name depends on the number of sides it has

# of Sides Name

3 Triangle

4 Quadrilateral

5 Pentagon

6 Hexagon

7 Heptagon

# of Sides Name

8 Octagon

9 Nonagon

10 Decagon

12 Dodecagon

N N-gon

Descriptions

Descriptions Describing Polygons

A polygons description depends on its shape

Convex: No line that contains a side of the polygon contains a point in the interior of the polygon

Non-Convex/Concave: A polygon that is not convex

Examples

Hexagon Concave

Heptagon

Convex

Heptagon

Concave

Heptagon

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Homework #7P. 44: 1-10, 14-21, 24, 25, 32-40, 43-53 odd