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.