Page 98 - Math Course 1 (Book 2)

Polygons

Mo. 9

Lesson 6 convex

If any of the lines of the polygon do not have any
point in the interior of the polygon, then it is convex.

KEY CONCEPTS:
1. Identify and name polygons.
2. Find the perimeter of a polygon on the No points of the
coordinate plane. lines are in the
3. Find perimeter or circumference and area interior.
of two-dimensional f gures.

MO. 9 - L6a Convex polygon

Identifying Polygons n-gon
A polygon with n sides is an n-gon.

Vocabulary A-Z Number Polygon
of
Let us learn some vocabulary Sides
3 triangle triangle square

4 quadrilateral
polygon 5 pentagon
A polygon is a closed f gure whose sides are all 6 hexagon pentagon hexagon
segments.
7 heptagon

A Z J K 8 octagon
9 nonagon octagon rectangle
H E 10 decagon

X Y 12 dodecagon
B C W G F
n n–gon circle oval
polygons ABC, WXYZ, EFGHJK

regular polygon
concave A convex polygon in which all the sides are
If any of the lines contain any point in the interior congruent and all the angles are congruent is
of the polygon, then it is concave. called a regular polygon.

Some of the lines pass
through the interior. regular
hexagon

Concave polygon

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