Checking and securing understanding of area for compound shapes | Maths

Starter quiz

The area is the size of the surface and states the number of unit ______ needed to completely cover that surface.

'squares' ✓
The area of this rectangle is ______ cm².

'11.76' ✓
The area of this parallelogram is ______ cm².

'13.25' ✓
The area of this triangle is ______ cm².

'88' ✓
The length of the edge marked 'b' is ______ cm.

'8' ✓
Which of these shapes has a different area to the other three?

Exit quiz

A composite rectilinear shape is a composite shape made from ______.

'rectangles' ✓
Laura uses the calculation 3 × 1.5 + 11 × 4 to work out the area of this composite rectilinear shape. Which diagram shows the way that Laura has subdivided the shape?
This compound rectilinear shape has been completed to make a rectangle. The additional rectangle has an area of ______ cm².

'80' ✓
This compound rectilinear shape has been completed to make a rectangle. Which of the following calculations are correct for finding the area of this composite rectilinear shape?

18 × 24 + 16 × 5

16 × 5 − 18 × 24

18 × 24 − 16 × 5 ✓

18 × 8 + 24 × 13
By rearranging the area, this compound shape is equivalent to ...

...a rectangle with dimensions of 20 m by 12 m

...a rectangle with dimensions of 19 m by 12 m ✓

...a rectangle with area of 228 m² ✓

...a rectangle with area of 240 m²
The area of this compound shape is ______ cm².

'315' ✓

Worksheet

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Lesson Details

Key learning points

There are multiple ways to find the area of compound shapes.
The most efficient method may depend on the features of the shape.
A method is to break the shape into shapes you can find the area of.
A method is to complete the shape.
A method is to rearrange the shape.

Common misconception

Pupils may multiply all given lengths.

Remind pupils that area is found by multiplying two perpendicular lengths from the shape and in some cases a coefficient (half for a triangle, pi for a circle). Trapeziums use the mean length of the parallel sides (one length).

Keywords

Area - The area is the size of the surface and states the number of unit squares needed to completely cover that surface.
Compound shape - A compound shape is a shape created using two or more basic shapes.
Composite shape - A composite shape is an alternative for a compound shape.