Definition: What are Irregular Shapes?
Irregular shapes are shapes where the sides and interior angles are different. They can be more challenging for children to identify, as they don’t resemble conventional shapes. On the other hand, regular shapes have sides that are all the same length and equal angles, so often, they’re a little easier to identify.
Consider looking around you in the classroom and bringing irregular shapes to life! Please pick up a pencil case, a book, an eraser, or a football, and discuss what makes them regular or irregular. You could go on a school scavenger hunt, encouraging your class to look for as many irregular 3D shapes as possible.
While rectangles may seem like regular shapes because they are standard and learned early in maths classes, they are irregular. For example, the only regular quadrilateral is a square because all sides and angles are of equal length.
When talking about different shapes, children will continue to use the names of the shapes. For instance, a shape with six sides of varying lengths and interior angles which measure differently is still a hexagon. However, they’ll often add the word ‘irregular’ in front of it to indicate that the shape’s sides and angles aren’t equal. So, they’ll call it an irregular hexagon.
Of course, there are more examples of irregular shapes – not just hexagons and rectangles. Furthermore, every shape can have a rare version. So let’s dive deeper to see what irregular 2D and irregular 3D shapes there are.
Irregular shape examples:
These are just a few polygons (fancy words for shapes) pupils will learn about in initial maths lessons. Next, they’ll practice recognizing the properties of these shapes and explaining why they’re irregular.
Irregular Triangle
For example, the right-angled triangle below is irregular because its sides aren’t equal, nor are its angles.
Most triangles are irregular unless they are of the equilateral variety! For example, isosceles triangles only have two sides of equal length, with one difference. And scalene triangles are unique because every side is a different length, making them irregular.
Irregular Pentagon
The irregular pentagon below also has sides and angles which aren’t equal.
Irregular Hexagon
It’s easy to notice that the length of the hexagon’s sides below differs. So is the size in degrees of its angles.
Irregular 3D Shapes
Pupils will not learn about irregular 3D shapes in primary school. But based on their knowledge of irregular polygons and 3D shapes, they can dive deeper and discover what makes a 3D shape irregular.
That’s done through understanding the types of polygons these shapes are made of. For example:
- Cube- a cube is a regular 3D shape because it has identical faces of regular polygons.
- Pyramid with a square base – on the other hand, a pyramid with a square as its base is an irregular 3D shape because it’s made of different polygons.
Is a Star an Irregular Shape?
It depends! This star is a regular pentagon because its sides’ lengths equal its interior angles. Therefore, there is nothing irregular about this shape.
However, you can create stars with different interior angles and side lengths. These would not be regular.
Teaching children about irregular shapes
Children begin to be introduced to shapes, including 2D and 3D, within their first years of school and extend their knowledge and understanding throughout their education. They learn how to:
- Draw 2D and 3D shapes
- Recognize angles as a shape or direction of turn
- Identify horizontal and vertical lines
- To understand polygons, including how many sides they should have
- Compare and classify geometric shapes, including quadrilateral triangles.
Their knowledge then develops by:
- Identifying 3D shapes, including cubes and cuboids.
- Understanding what makes polygons irregular – based on equal sides and edges.
- Compare and classify geometric shapes, their properties, and sizes and find unknown angles in triangles and quadrilaterals.
