# Polygons by Amy Pihlainen

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Polygons by Amy Pihlainen

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Polygons by Amy Pihlainen

Polygons The word polygon means “many angles” A two dimensional object A closed figure

More about Polygons Made up of three or more straight line segments There are exactly two sides that meet at a vertex The sides do not cross each other

Examples of Polygons

These are not Polygons

Terms: Side: One of the line segments that make up a polygon. Vertex: point where two sides meet.

Terms continued Interior angle: an angle formed by two adjacent sides inside the polygon. Exterior angle: an angle formed by two adjacent sides outside the polygon.

Terms continued

Types of Polygons Equiangular Polygon: a polygon in which all of the angles are equal Equilateral Polygon: a polygon in which all of the sides are the same length

Types of Polygons continued
Regular Polygon: a polygon where all the angles are equal and all of the sides are the same length. They are both equilateral and equiangular

Examples of Regular Polygons

Names of Polygons Triangle: a three sided polygon Quadrilateral: a four sided polygon. A quadrilateral that is a regular polygon is called a square.

Names continued Pentagon: a five sided polygon
Hexagon: a six sided polygon Heptagon: a seven sided polygon

Names continued Octagon: an eight sided polygon Decagon: a ten sided polygon Dodecagon: a twelve sided polygon

Sides Name Nonagon, Enneagon Undecagon, Hendecagon Tridecagon, Triskaidecagon Tetradecagon, Tetrakaidecagon Pentadecagon, Pentakaidecagon Hexadecagon, Hexakaidecagon Heptadecagon, Heptakaidecagon Octadecagon, Octakaidecagon Enneadecagon, Enneakaidecagon Icosagon Triacontagon Tetracontagon Pentacontagon Hexacontagon Heptacontagon Octacontagon Enneacontagon Hectogon, Hecatontagon 1, Chiliagon 10, Myriagon

Types of Polygons Convex - a straight line drawn through a convex polygon crosses at most two sides. Every interior angle is less than 180°. Concave - you can draw at least one straight line through a concave polygon that crosses more than two sides. At least one interior angle is more than 180°.