  # Regular and Irregular Polygons

In this worksheet, students distinguish between regular and irregular polygons based on reasoning about equal sides and angles. This content is premium and exclusive to EdPlace subscribers. Key stage:  KS 2

Curriculum topic:   Maths and Numerical Reasoning

Curriculum subtopic:   2D Shapes: Triangles, Quadrilaterals and Polygons

Difficulty level:   #### Worksheet Overview

In this worksheet, you must decide whether a polygon is regular or irregular.

The word polygon comes from the Greek language:

polús means many and gõnía means angles.

A polygon is a flat shape with straight sides that are joined to form a closed shape. It will have several angles.

Regular polygons

A regular polygon is one in which all the sides are equal in length and all the interior angles are equal in size. A square has 4 equal sides and 4 equal angles of 90°. A regular pentagon has 5 equal sides and 5 equal angles of 108°. A regular octagon has 8 equal sides and 8 equal angles of 135°.

Irregular polygons

An irregular polygon is one in which either all the sides are not equal in length and/or all the interior angles are not equal in size. This triangle is scalene. It has sides of 3 different lengths and 3 different angles. It is irregular. This pentagon has three 90° angles, but also two angles which are larger. The sides are of differing lengths. It is irregular.

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