New
New
Year 5

# Calculate the area of shapes made from 2 or more rectangles

I can calculate the area of shapes made from 2 or more rectangles.

New
New
Year 5

# Calculate the area of shapes made from 2 or more rectangles

I can calculate the area of shapes made from 2 or more rectangles.

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## Lesson details

### Key learning points

1. To find the area of a rectangle you multiply the length by the width.
2. Compare different methods to decompose shapes and decide which is the most efficient.
3. Choose the most efficient calculation strategies to calculate the area of a compound rectilinear shape.

### Common misconception

There is only one way to split a compound shape to calculate the area.

Make time in the lesson to model and discuss different ways of calculating the area of compound shapes. Include strategies that move parts of the shape to simplify the shape and the calculations needed.

### Keywords

• Compound - A compound shape is made up of two or more shapes.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Starter quiz

### 6 Questions

Q1.
Match the multiplication equation to the correct answer.
Correct Answer:25 x 8 ,= 200

= 200

Correct Answer:20 x 12 ,= 240

= 240

Correct Answer:2 x 125 ,= 250

= 250

Correct Answer:30 x 7 ,= 210

= 210

Q2.
Which of these compound shapes has the largest area?
a
Q3.
Which would be the most efficient strategy to calculate the area of this compound rectilinear shape?
Split it into two rectangles using a vertical line. Combine the two areas.
Correct answer: Draw a rectangle around the shape. Subtract the area of the gap rectangle.
Split it into two rectangles using a horizontal line. Combine the two areas.
Q4.
What are the missing dimensions for the square?
12 cm and 12 cm
11 cm and 12 cm
11 cm and 10 cm
Correct answer: 11 cm and 11 cm
Q5.
Tick all the possible pairs of dimensions from the list.
3 cm and 10 cm
Correct answer: 32 cm and 1 cm
Correct answer: 16 cm and 2 cm
Correct answer: 8 cm and 4 cm
4 cm and 6cm
Q6.
The area of this compound shape is 227 cm². What is the missing dimension?
5 cm²
8 cm²
6 cm²

## Exit quiz

### 6 Questions

Q1.
A shape is one that is made up of two or more shapes.
rectangle
rectilinear
square
Q2.
This is an image of the French flag. It consists of three rectangles of equal size. Calculate the area of the blue part. cm²
Correct Answer: 63 , 63 cm², 63 centimetres squared, 63 square centimetres
Q3.
This image is of the flag from the Netherlands. It consists of three rectangles of equal size. Calculate the total area of the flag. cm²
Correct Answer: 99, 99 cm², 99 centimetres squared, 99 square centimetres
Q4.
This rectilinear shape is made up of four identical rectangles. Choose an efficient method to calculate the area. A = cm²
Correct Answer: 96, 96 cm², 96 centimetres squared, 96 square centimetres
Q5.
Laura has chosen to decompose this compound rectilinear shape into two rectangles. Which multiplications will she use to help calculate the area?
Correct answer: 9 cm × 6 cm
11 cm × 9 cm
11 cm × 3 cm
Correct answer: 3 cm × 5 cm
Q6.
To calculate an area of the playground, Luca has chosen to calculate the whole area and then subtract the missing part. Correctly order the calculations that he would do.
1 - 12 m × 11 m = 132 m²
2 - 3 m × 3 m = 9 m²
3 - 132 m² - 9 m² = 123 m²