 # 9.02 Splitting 2D shapes

Lesson

## Ideas

Let's review the  names of 2D shapes  .

### Examples

#### Example 1

What is the name of the shape below?

A
Triangle
B
Rectangle
Worked Solution
Create a strategy

Think of a shape that has 2 pairs of opposite sides with equal lengths.

Apply the idea

From the option above, the shape that has 2 pairs of opposite sides with an equal length is a rectangle.

So the correct option is B: Rectangle

Idea summary

To help work out the name of a shape, think about properties like:

• How many sides it has

• What sides are the same length

## Split 2D Shapes

Let's look at how some familiar 2D shapes can be broken up into other shapes.

### Examples

#### Example 2

The shape below can be made up of which three shapes?

A
B
C
Worked Solution
Create a strategy

Slice the shape to see what shapes we can make.

Apply the idea

We can break up the shape like this:

After breaking up the dotted line on the shape, we have 2 triangles and 1 horizontal rectangle. So, the correct option is A.

Idea summary

If we start with a two dimensional (2D) shape, we can break it into other 2D shapes.

## Combine 2D shapes

Let's go the other way and put shapes together to build other shapes. It's kind of like a puzzle.

### Examples

#### Example 3

The five shapes below can be combined to make which of the following composite shapes?

A
B
Worked Solution
Create a strategy

Think about which shape can be made with 4 triangles and 1 square.

Apply the idea

The shape in option A is made up of 4 triangles and 1 square.

The shape in option B is made up of 3 triangles.

So, the correct answer is option A.

Idea summary

We can join, or combine, shapes together to make new shapes.

### Outcomes

#### MA2-15MG

manipulates, identifies and sketches two-dimensional shapes, including special quadrilaterals, and describes their features