New
New
Introduction to enlargements
I can understand the nature of enlargements and appreciate what changes and what is invariant
Lesson 12 of 18
New
New
- Year 7
Introduction to enlargements
I can understand the nature of enlargements and appreciate what changes and what is invariant
Lesson details
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.
Pupils will need square paper and scissors to complete question 2 of Task B.
Teacher tip
Licence
This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
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.
The object is what we call a shape after it has been transformed.
True
Q2.Which property is not invariant when a shape is translated?
Which property is not invariant when a shape is translated?
side lengths
angles
orientation
Q3.Which properties are not invariant when a shape is rotated?
Which properties are not invariant when a shape is rotated?
side lengths
angles
Q4.Which properties are not invariant when a shape is reflected?
Which properties are not invariant when a shape is reflected?
side lengths
angles
Q5.Match each number on the left with its multiple on the right. There is only one possible solution.
Match each number on the left with its multiple on the right. There is only one possible solution.
Q6.Which of these is the correct location of the reflected image of vertex A?
Which of these is the correct location of the reflected image of vertex A?
a
b
c
Assessment exit quiz
6 Questions
Q1.__________ is a transformation that causes a change of size.
__________ is a transformation that causes a change of size.
Q2.Two shapes are if the only difference between them is their size.
Two shapes are if the only difference between them is their size.
Q3.Enlarging a shape means the shape will always get bigger.
Enlarging a shape means the shape will always get bigger.
True
Q4.Which property is invariant when a shape is enlarged?
Which property is invariant when a shape is enlarged?
side lengths
position
Q5.Sofia is going to halve the size of a rectangle. What will happen to the angles?
Sofia is going to halve the size of a rectangle. What will happen to the angles?
They will all double in size.
They will all halve in size.
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?
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?
1.3 cm
2.6 cm
5.2 cm
