1. Enlargements and negative scale factors
Grade 5
Enlargements and negative scale factors
Identify and construct enlargements including using negative scale factors
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2. Lesson Plan Lesson Overview Progression of Learning
Objective(s)
Identify and construct enlargements including using negative scale factors
Grade 5
Prior Knowledge
Simple enlargements
Scale factors (integers and fractions)
Duration
Allow 40 minutes to cover the objective of this lesson
Resources
Print slides: 4, 11, 13
Equipment
Ruler
Progression of Learning
What are the students learning?
How are the students learning? (Activities & Differentiation)
How to do and describe a enlargement (positive integer scale factor)
Give students slide 4 printed. Variations here with or without a centre of enlargement. Discuss scale factor and positioning of the enlarged shape. Describing often helpful to have a ruler. 15
Positioning of enlarged shape with scale factor is negative
Using slide 10 demonstrate the affect of a negative scale factor. Encourage students to describe the journey either using words (left, right, up, down) or by using the arrows. Give students slide 11 to practice a further example independently. 10
Applying negative scale factors to enlargement questions
Give students slide 13 printed. This includes 4 different questions – all negative scale factors (including some fractional scale factors) with different centre of enlargements. Allow students to attempt these questions on their own before using slides 14 to 17 to review the solution to each question.
There are no exam questions in the OCR SAMS related to this objective. However, the questions on slide 13 have been taken from Edexcel SAMS so exam style practice questions have been incorporated.
Next Steps
Negative and fractional scale factors for enlargement
Assessment
PLC/Reformed Specification/Target 5/Geometry and Measures/Enlargements And Negative Scale Factors

3. Key Vocabulary
Centre Enlargement Negative Scale factor

4. Describe Transformation
Enlargement
Enlarge scale factor 2, centre A (1,1)
Enlarge
scale factor 2
Enlarge scale factor 3, centre (1,2)
Describe Transformation 1. 2. 3. 1. 2. 3.
Student Sheet 1

5. Enlargement Solutions
Enlarge scale factor 2

6. Enlarge scale factor 3, centre (1,2)
Enlargement Solutions
Enlarge scale factor 3, centre (1,2)
Visualier
Guide

7. Enlarge scale factor 2, centre A (1,1)
Enlargement Solutions
Enlarge scale factor 2, centre A (1,1)
1 min head start

8. Describe Transformation
Enlargement Solutions
Describe Transformation 4
1. Enlargement
2. Scale Factor 4
3. Centre (1,1)
Guide vis 8 1 2

9. Describe Transformation
Enlargement Solutions
Describe Transformation 5
1. Enlargement
2. Scale factor 2.5
3. Centre (0, 0)
1 min head start 2

10. Enlarge the object by scale factor -1 from the centre (2,1)
How to…apply a negative enlargement
Enlarge the object by scale factor -1 from the centre (2,1)
Centre to original shape
Inverse Directions A B C

11. Enlarge the object by scale factor - 2 from the centre (2,1)
You try to…apply a negative enlargement
Enlarge the object by scale factor - 2 from the centre (2,1)
Centre to original shape
Inverse Directions
Student Sheet 2

12. Enlarge the object by scale factor - 2 from the centre (2,1)
You try to…apply a negative enlargement
Enlarge the object by scale factor - 2 from the centre (2,1)
Centre to original shape
Inverse Directions A B C

13. Practice Questions
Student Sheet 3

14. Practice Q1 Right 1 Up 1 Scale Factor = -2 Opp Direction x 2 Left 2
Down 2

15. Practice Q2 -2

16. Practice Q3

17. Practice Q4