A polygon is any closed figure with three or more straight sides. "Closed" means that there are no gaping holes in it and that all sides connect together.
These Are Polygons:
These Are Not Polygons:
That's right, a circle is not a polygon. It doesn't have all the properties, and it's really hard to count the number of sides.
Names of Some Common Polygons
|Number of Sides||Number of Angles||Name|
|7||7||Septagon (or Heptagon)|
Polygons have a lot of important vocabulary terms that come with them. You will need to memorize these, but don't worry, they aren't too difficult.
- Angle: the shape formed when two rays meet at a common point. AKA "the corner."
- Vertex: the point where two rays meet; the corner point of a polygon. The plural of vertex is vertices.
- Side: the straight edge of a polygon.
- Equiangular: a figure where all angles are equal in measure.
- Equilateral: a figure where all sides are equal in length.
- Regular Polygon: an equilateral, equiangular polygon.
You're probably familiar with these shapes
These Are Not Regular
Base and Height of a Polygon
- Base: the bottom side of a polygon.
- Height: the height of a polygon is the perpendicular distance from the top-most vertex to the base. The height and base ALWAYS form a right angle.