Using the scale factor for enlarging an area
I can calculate the scale factor used to enlarge an area and use it to find missing lengths.
Using the scale factor for enlarging an area
I can calculate the scale factor used to enlarge an area and use it to find missing lengths.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- You can calculate the scale factor from the two areas.
- Having calculated the scale factor, you can find missing lengths.
Keywords
Similar - Two shapes are similar if the only difference between them is their size. Their side lengths are in the same proportions.
Invariant - A property of a shape is invariant if that property has not changed after the shape is transformed.
Enlargement - Enlargement is a transformation that causes a change of size.
Scale factor - A scale factor is the multiplier between similar shapes that describes how large one shape is compared to the other.
Common misconception
A linear scale factor can only be found by finding the multiplicative relationship between two corresponding lengths.
A linear scale factor can also be found by square rooting an area scale factor, where an area scale factor is found from the multiplicative relationship between the area of two similar 2D shapes, or corresponding faces on two similar 3D shapes.
To help you plan your year 10 maths lesson on: Using the scale factor for enlarging an area, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 10 maths lesson on: Using the scale factor for enlarging an area, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 4 maths lessons from the Similarity unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Starter quiz
6 Questions



Linear scale factor: $$5$$ -
Area scale factor: $$25$$
Linear scale factor: $$\frac{1}{2}$$ -
Area scale factor: $$\frac{1}{4}$$
Linear scale factor: $$3$$ -
Area scale factor: $$9$$
Linear scale factor: $$0.1$$ -
Area scale factor: $$0.01$$
Linear scale factor: $$10$$ -
Area scale factor: $$100$$
Linear scale factor: $$\frac{3}{2}$$ -
Area scale factor: $$\frac{9}{4}$$

Exit quiz
6 Questions




