Page 654 - Basic College Mathematics with Early Integers
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9.2 PLANE FIGURES AND SOLIDS Objectives
Identify Plane Figures.
In order to prepare for the sections ahead in this chapter, we first review plane Identify Solids.
figures and solids.
Objective Identifying Plane Figures
Recall from Section 9.1 that a plane is a flat surface that extends indefinitely.
Plane
A plane figure is a figure that lies on a plane. Plane figures, like planes, have
length and width but no thickness or depth.
A polygon is a closed plane figure that basically consists of three or more line
segments that meet at their endpoints.
A B C D E
A regular polygon is one whose sides are all the same length and whose angles
are the same measure.
F G H I J K
A polygon is named according to the number of its sides.
Polygons
Number of Sides Name Figure Examples
3 Triangle A, F
4 Quadrilateral B, E, G
5 Pentagon H
6 Hexagon I
7 Heptagon C
8 Octagon J
9 Nonagon K
10 Decagon D
Some triangles and quadrilaterals are given special names, so let’s study these
polygons further.We begin with triangles.
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