Calculate the area of compound rectilinear shapes | Maths

Starter quiz

Match the start and end of the sentences to describe the shapes correctly.
- A shape with all right angles
  
  ⇔
  
  is a rectilinear shape. ✓
- A shape made of two or more shapes
  
  ⇔
  
  is a compound shape. ✓
The area of a compound shape made of two rectangles can be calculated by ______ the area of each rectangle.
- dividing
- multiplying
- adding ✓
What is the total area of this compound rectilinear shape? ______ m².
- '70' ✓
Which times table fact is needed to calculate the missing area in this rectilinear shape?
- 13 m x 8 m
- 10 m x 8 m ✓
- 8 m x 3 m
Which multiplications are needed to calculate the area of the shape?
- 7 × 5
- 15 × 5 ✓
- 15 × 2 ✓
- 2 × 5
Calculate the area of this rectilinear shape? ______ cm²
- '64' ✓

Exit quiz

Match the parts of the sentences correctly.
- A rectangle
  
  ⇔
  
  has four right angles. ✓
- A compound shape
  
  ⇔
  
  is made up of two or more shapes. ✓
- A rectilinear shape
  
  ⇔
  
  has angles that are all right angles. ✓
- A compound rectilinear shape
  
  ⇔
  
  is made up of two or more rectangles. ✓
We can calculate the area of compound rectilinear shapes by splitting it into ______.
- 'rectangles' ✓
Look at this compound rectilinear shape. Which statements are true?
- c + d = 9 cm ✓
- side a is 9 cm
- 12 cm = b + a ✓
- I don't know the lengths of sides a and b
Look at this shape. The total length of sides a and d is ______ cm.
- '12' ✓
What is the missing length 'a' on this shape? ______ cm
- '10' ✓
Calculate the area of this compound rectilinear shape. A = ______ cm²
- '90 ' ✓

Worksheet

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Lesson Details

Key learning points

Use addition and subtraction to calculate missing side lengths in compound rectilinear shapes.
Identify two different lengths which total another side length in a compound rectilinear shape.
Use knowledge of the area of a rectangle to calculate the area of shapes made from two rectangles.

Common misconception

Calculating the length of a side when the overall dimension and part dimensions are known and understanding when a part of the overall dimension is needed to calculate part of the area.

Look at shapes with missing dimensions and discussing that the overall length and width of a compound rectilinear shape is the total of the shorter side lengths in a particular direction. This allows missing or overall dimensions to be calculated.

Keywords

Compound - A shape made up of two or more other shapes is known as compound.
Rectilinear - A shape where all angles composed of right angles is called a rectilinear shape.