Sort 2D and 3D shapes - Maths - Learning with 91�ȱ� Bitesize

Sorting shapes

To sort 2D and 3D shapes, we use different properties like the number of sides or faces.

2D shapes

JJ is sorting these shapes in order from fewest sides to most sides.

A triangle, two pentagons and a rectangle.

Let's count the number of sides.

When counting sides be careful not to count the same side twice.

Triangle with 3 sides numbered, two pentagons with 5 sides numbered and a rectangle with 4 sides numbered.

Now we know how many sides each shape has we can put them in order from fewest sides to most sides.

Shapes sorted from fewest sides to most sides.

Why is investigating important?

Investigating is an important part of maths because we notice different patterns and rules.

Did you notice that two of the shapes had the same number of sides but looked different?

Sorting shapes by vertices

Another way to sort shapes is by number of corners. In maths we call corners vertices.

Let's take another look at the shapes and this time count the vertices.

Shapes sorted from fewest vertices to most vertices.

Do you notice a pattern?

2D Shapes have the same number of vertices as sides.

3D shapes

What can you find out by investigating the properties of 3D shapes?

JJ needs help investigating the number of vertices, faces and the number of edges of this shape.

Can you count the vertices and faces with him?

He is going to use a table to organise his findings.

Table with columns for 3D shape, vertices, faces and edges with 4 vertices and 4 faces noted.

Child with a thought bubble with a lightbulb.

Investigating is all about testing ideas.

JJ thinks that 3D shapes have the same number of edges as vertices just like the pattern we spotted earlier that 2D shapes have the same number of vertices as sides.

Let's count the number of edges and test his theory.

Table with a 3D shape showing 4 vertices, 4 faces and 6 edges

The shape has 6 edges.

JJ's theory was incorrect.

Remember, having ideas that turn out to be wrong is ok - this is why investigating is such an important part of maths!

Example 1

Did you notice that this shape has the same amount of vertices as faces?

Does that mean all 3D shapes have the same amount of vertices and faces?

Let's test that theory - count the faces, vertices and edges of these 3D shapes.

Three 3D shapes in a table with the headings vertices, faces and edges

Let's see if the theory is correct.

Three 3D shapes in a grid. First shape has 8 vertices, 6 faces and 12 edges. Second shape has 4 vertices, 4 faces and 6 edges. Third shape shape has 8 vertices, 6 faces and 12 edges.

Not all 3D shapes have the same number of vertices and faces so the theory was incorrect.

Don’t be afraid to make mistakes – mistakes help you learn.

This is what investigating is all about!

Activities

Quiz

This quiz will help you practise sorting 2D shapes.

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