Starter quiz
- Double 17 is ______
- '34' ✓
- Multiply 16 by 4
- '64' ✓
- Which of these is the same as dividing by two?
- Dividing by one-half
- Multiplying by one-half ✓
- Adding one-half
- Multiplying by one-quarter
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- Match the words to their correct definitions.
- Transform⇔Change something ✓
- Enlarge⇔Make something larger ✓
- Reduce⇔Make something smaller ✓
- Match the equations to the correct product.
- 5 × 6 =⇔30 ✓
- 4 × 7 =⇔28 ✓
- 12 × 2 =⇔24 ✓
- 3 × 9 =⇔27 ✓
- Which of the following are multiples of 7?
- 28 ✓
- 34
- 40
- 42 ✓
- 49 ✓
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Exit quiz
- Select all of the scale factors where the result would be a shape with a greater length and width than the original.
- Scale factor of 1
- Scale factor of one-half
- Scale factor of 2 ✓
- Scale factor of one-third
- Scale factor of 3 ✓
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- Shape A is a square with a side length of 3 cm and Shape B is a square with a side length of 12 cm. Shape A has been scaled by a scale factor of ______ to create Shape B.
- '4' ✓
- Shape A is an equilateral triangle with a side length of 3 cm and Shape B is an equilateral triangle with a side length of 9 cm. Shape A has been scaled by a scale factor of ______ to create Shape B.
- '3' ✓
- Shape A is a square with a side length of 3 cm which has been scaled by a scale factor of 3 to get Shape B. What is the perimeter of Shape B? ______ cm.
- '36' ✓
- Shape A is a triangle with a side length of 3 cm which has been scaled by a scale factor of 4 to get Shape B. What is the perimeter of Shape B? ______ cm.
- '36' ✓
- Select all of the scale factors where the result would be a shape with a smaller length and width than the original.
- Scale factor of one-half ✓
- Scale factor of 2
- Scale factor of one-third ✓
- Scale factor of 3
- Scale factor of one-quarter ✓
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- If the lengths of the sides of a shape have been doubled, the perimeter will be double.
- If the side lengths of a shape are multiplied by the same factor the perimeter will be multiplied by the same factor.
- The number which all the sides have been multiplied by is called a scale factor.
Common misconception
Pupils may remember to scale one of the sides (or pairs of sides) of a shape but forget to scale the others.
Focus attention on what it means when a shape is similar, drawing on examples and non-examples to support learners to understand how scaling affects all side lengths.
Keywords
Perimeter - Perimeter is the distance around a two-dimensional shape.
Scale factor - A scale factor is the multiplier between similar shapes that describes how large one shape is compared to the other.
Similar - Two shapes are similar when one shape can become the other after a resize, flip, slide or turn.
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