Introduction to enlargements
Lesson details
Learning outcome
I can understand the nature of enlargements and appreciate what changes and what is invariant
Key learning points
- An enlargement means a change in size.
- The lengths of the lines may change when enlarged.
- The angles inside an object do not change when enlarged.
- When an object is enlarged, the image is similar.
Keywords
Enlargement - Enlargement is a transformation that causes a change of size.
Similar - Two shapes are similar if the only difference between them is their size. Their side lengths are in the same proportions.
Common misconception
Enlargement only refers to an increase in size.
The transformation 'enlargement' refers to a change of size that can be either a stretch or a shrink.
Teacher tip
Pupils will need square paper and scissors to complete question 2 of Task B.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.The object is what we call a shape after it has been transformed.
Q2.Which property is not invariant when a shape is translated?
Q3.Which properties are not invariant when a shape is rotated?
Q4.Which properties are not invariant when a shape is reflected?
Q5.Match each number on the left with its multiple on the right. There is only one possible solution.
6
9
16
30
Q6.Which of these is the correct location of the reflected image of vertex A?
Assessment exit quiz
6 Questions
Q1.__________ is a transformation that causes a change of size.
Q2.Two shapes are if the only difference between them is their size.
Q3.Enlarging a shape means the shape will always get bigger.
Q4.Which property is invariant when a shape is enlarged?
Q5.Sofia is going to halve the size of a rectangle. What will happen to the angles?
Q6.Aisha's rectangle has a length of 6 cm and a width of 1.3 cm. A similar rectangle has a length of 18 cm. What will its width be?
To help you plan your 7 maths lesson on: Introduction to enlargements, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 7 maths lesson on: Introduction to enlargements, 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.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 3 maths lessons from the Transformations unit, dive into the full secondary maths curriculum, or learn more about lesson planning.