Polygons

Concept

A polygon is given as a closed two-dimensional figure with three or more straight lines. The Greek word “Polygon” consists of Poly meaning “many” and gon meaning “angle”.

A polygon can be categorized as regular and irregular polygon based on the length of its sides. A polygon which has all its sides of equal length and all its angles of equal measures is called a regular polygon. A polygon which has all its sides of unequal length and all its angles of unequal measures is called an irregular polygon.

Rules

We can identify a polygon by checking the following characteristics in a shape:
– It is a closed shape, that is, there is no end that is left open in the shape. It ends and begins at the same point.
– It is a plane shape, that is, the shape is made of line segments or straight lines.
– It is a two-dimensional figure, that is, it has only two dimensions length and width. There is no depth or height to it.
– The shape must have three or more sides.
– The angles in the polygon may or may not be the same.
– The length of the sides of a polygon may or may not be the same.

Example

Which of the following shapes are octagons?

Solution

Octagons are polygons that have 8 sides and 8 corners.

Practice Polygons

Practice Problem 1

Is this shape a polygon, an open shape, or both?

Practice Problem 2

How many sides does a hexagon have?

Practice Problem 3

Drag the shapes to the names.

Practice Problem 4

Ruth is preparing a birthday card for her friend. She cut it out in a shape that has all four equal sides. Which of the following is the shape of the birthday card that Ruth prepared?