 # 10.03 Find areas using a grid

Lesson

## Ideas

Let's try this problem to review how to  compare the area  of shapes.

### Examples

#### Example 1

Which shape has the smallest area?

A
B
Worked Solution
Create a strategy

Choose the shape that takes up less space.

Apply the idea

The shape in option A is taking up less space than the shape in option B.

The shape that has the smallest area is option A.

Idea summary

When comparing areas of shapes, the shape that takes up less space is the smallest.

## Compare area

We can measure area in shapes such as squares and rectangles, but what about different shapes?

To help us measure the area of shapes like the ones pictured below, we can use square units.

In this video, we look at how to calculate the area of shapes similar to those in the picture shown.

### Examples

#### Example 2

Find the area of the shape by counting the number of grid squares it covers.

Each grid square represents 1 square unit.

Worked Solution
Create a strategy

Count the total number of the shaded squares to find the area.

Apply the idea

\text{Area}=32 \text{ square units}

Idea summary

To find the area of a shape on a grid, we can count the number of unit squares inside the shape.

## Different shapes

Sometimes we have unusual shapes but we can still work out the area of these shapes by counting the number of square units inside. We can also work out the area of triangles.

### Examples

#### Example 3

Find the area of the shape by counting the number of grid squares it covers.

Each grid square represents 1 square unit.

Worked Solution
Create a strategy

Count the total number of fully shaded squares and combine the half shaded squares to make 1 square unit.

Apply the idea

There are 2 shaded squares and 4 halves. The 4 halves can be combined to make 2 more shaded squares:

Idea summary

We can combine half square units inside a shape to make whole square units in order to find the area.

## Area of shapes

This video shows us how unit squares can help us find the area of a shape.

### Examples

#### Example 4

Find the area of the shape below.

Worked Solution
Create a strategy

Count the total number of squares.

Apply the idea

There are 5 square inside the shape.

\text{ Area }= 5\, \text{units}^2

Idea summary

To find the amount of space a shape takes up, we can use a unit square.

### Outcomes

#### MA2-10MG

measures, records, compares and estimates areas using square centimetres and square metres