Page 48 - Math Course 2 (Book 2)

Polygons
Mo. 8

Lesson 3 interior angles
An interior angle is an angle inside a polygon.

interior
KEY CONCEPTS: angle Exterior
1. Classify polygons. angle
2. Determine the sum of the measures of the Diagonal
interior and exterior angles of a polygon. Side

Vertex→
MO. 8 - L3a

regular polygon
Classify Polygons A regular polygon is a polygon that is equilateral
(all sides are congruent) and equiangular
(all angles are congruent). Since the angles of a
Vocabulary A-Z regular polygon are congruent, their measures are
equal.
Let us learn some vocabulary

polygon
A polygon consists of a sequence of consecutive
line segments placed end to end to form a simple
closed figure.

The line segments meet only at
their endpoints

The line segments are called
sides. Regular Polygons

The points of intersection are
called vertices.

diagonal
A diagonal is a line segment in a polygon that joins Triangle Quadrilateral Pentagon Hexagon
5 sides
4 sides
6 sides
3 sides
two nonconsecutive vertices.
interior
angle
Exterior
angle
Diagonal Heptagon Octagon Nonagon Decagon
Side 7 sides 8 sides 9 sides 10 sides

quadrilateral Pentagon
Vertex→

hexagon heptagon octagon
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