Investigating Middle School Mathematics On-Line
Henrico County Public Schools
Polygons
A polygon is a simple closed curve consisting entirely of a finite number of line segments which form the sides of the polygon. A line segment is the set of all points that lie on the line between two given points called the end points of the line segment. A simple close curve is a set of connected points that does not intersect itself at any point other than begins and ends at the same point.
| We give special names to common polygons. | |
| triangle | A polygon made with three line segments (sides). |
| quadrilateral | A polygon made with four line segments (sides). |
| pentagon | A polygon made with five line segments (sides). |
| hexagon | A polygon made with six line segments (sides). |
| heptagon | A polygon made with seven line segments (sides). |
| octagon | A polygon made with eight line segments (sides). |
| n-gon | A polygon made with n line segments (sides). |
The best way to remember these names is to identify and recognize the prefix (first few letters) of each name.
Regular Polygons
If all sides of a polygon have equal lengths and if all angles have the same measure then the polygon is called a Regular Polygon. Below you will pictures of some common regular polygons.
| A regular triangle is called an Equilateral Triangle. A regular quadrilateral is called a Square. |
Equilateral Triangle |
Square |
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Regular Pentagon |
Regular Hexagon |
Regular Octagon |
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Investigation Steps
Graphic Organizers