# Geometry Section 6.1 Polygons 4/15/2017.

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Geometry Section 6.1 Polygons 4/15/2017

1. A plane figure formed by three or more segments called sides.
Polygon 1. A plane figure formed by three or more segments called sides. 2. Each side intersects exactly two other sides, one at each endpoint Sides: the segments that form the polygon. Vertex: an endpoint of a side of the polygon No Curves! A closed figure.

Identifying Polygons C D A B E one of its sides intersects
more than two other sides B some of its sides are not segments (No curves allowed!) E two of the sides intersect only one other side (Must be a closed figure)

Names 3 Triangle 4 5 Quadrilateral 6 7 Pentagon 8 9 Hexagon 10 12
Polygons are named by the # of sides they have 3 4 5 6 7 8 9 10 12 n Triangle Quadrilateral Pentagon Hexagon Heptagon Octagon Nonagon Decagon Dodecagon n-gon

all interior angles are
Convex polygon: If you extend any of the sides, the side will not cut through the polygon. Equilateral polygon: All sides are Equiangular polygon: all interior angles are Concave polygon: If you extend a side, the side may cut through the polygon.

Identifying Convex and Concave Polygons
Identify the polygon and state whether it is convex or concave 6 hexagon convex 7 heptagon concave

Regular polygons A polygon is regular if it is both
__________and ___________ Diagonal: ____________________ ____________________. equilateral equiangular. A segment that joins two nonconsecutive vertices.

Quadrilateral Pentagon Hexagon Convex Concave Convex Not regular Not regular Regular

360 360 5(20)= 100 360 3(20)+10= 70 x = 20

First, solve for x

End Assignment: Pg.325 #12-34 even, odd

Geometry Section 6.1 Polygons 4/15/2017

Polygon Sides: Vertex:

Identifying Polygons

Names Polygons are named by the # of sides they have 3 4 5 6 7 8 9 10 12 n

Equilateral polygon: Equiangular polygon: Concave polygon:
Convex polygon: Equilateral polygon: Equiangular polygon: Concave polygon:

Identifying Convex and Concave Polygons
Identify the polygon and state whether it is convex or concave

Regular polygons A polygon is regular if it is both
__________and ___________ Diagonal: ____________________ ____________________.