Angles Of Polygons
More Geometry Lessons
In this lesson, we will learn
A polygon is a closed shape that has three or more sides. Each side is a line segment. The line segments form the sides of the polygon.
The following are examples of polygons:
The following figures are not polygons:
The sides of a simple polygon do not intersect. In a simple polygon, the line segments meet in pairs to form the vertices. Usually the word "simple" is omitted and the word "polygon" is used to mean "simple polygon".
A complex polygon has intersecting sides.
A convex polygon has all angles less than 180°.
A concave polygon has at least one angle greater than 180°. (memory tool: concave has a "cave" in it)
An equilateral polygon is a polygon which has all sides of the same length. A rhombus is an example of an equilateral polygon.
An equiangular polygon is a polygon whose interior angles are equal. A rectangle is an example of an equiangular polygon.
A regular polygon is a polygon with equal sides and equal angles otherwise it is an irregular polygon. A regular polygon is both equilateral and equiangular.
Some polygons have special names, depending on the number of sides they have.
The following table gives the names and properties of polygons with different number of sides. Scroll
down the page for more examples and solutions.
For polygons with more sides, it is easier and quite common to use a number to indicate the number of sides. For eg. 15-gon or 23-gon.
Practice the names of polygons with the following worksheets
Number of Sides In Polygons - Give the number of sides.
Names of Polygons - Give the names of polygons.
How to define a polygon?
How to distinguish between concave and convex polygons?
How to name polygons?
What is the difference between a regular and irregular polygons?
The following video explains what are polygons, defines regular and irregular polygons and their features.
Interior Angles in Convex Polygons
The following video will show you the different types of polygons based on their sides and angles measures.
Examples of classifying polygons
Convex Hexagon, Concave Octagon, Convex Equilateral Nonagon.
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