10.1 Naming Polygons

Naming Polygons

You will learn to name polygons according to the number of _____ and ______.

1) regular polygon

2) convex

3) concave

sides angles

Naming Polygons

A polygon is a _____________ in a plane formed by segments, called sides.closed figure

A polygon is named by the number of its _____ or ______.sides angles

A triangle is a polygon with three sides. The prefix ___ means three.tri

Naming Polygons

Prefixes are also used to name other polygons.

Prefix Number ofSides

Name ofPolygon

tri-

quadri-

penta-

hexa-

hepta-

octa-

nona-

deca-

3

4

5

6

7

8

9

10

triangle

quadrilateral

pentagon

hexagon

heptagon

octagon

nonagon

decagon

Naming Polygons

U

TS

Q

R

P

A vertex is the point of intersection of two sides.

A segment whoseendpoints arenonconsecutivevertices is adiagonal.

Consecutive vertices arethe two endpoints of anyside.

Sides that share a vertexare called consecutive sides.

Naming Polygons

An equilateral polygon has all _____ congruent.

An equiangular polygon has all ______ congruent.

sides

angles

A regular polygon is both ___________ and ___________.equilateral equiangular

equilateralbut not

equiangular

equiangularbut not

equilateral

regular,both equilateraland equiangular

Investigation: As the number of sides of a series of regular polygons increases, what do younotice about the shape of the polygons?

Naming Polygons

A polygon can also be classified as convex or concave.

If all of the diagonalslie in the interior of the figure, then the

polygon is ______.convex

If any part of a diagonal liesoutside of the figure, then thepolygon is _______.concave

Naming Polygons