Year 6 · Maths · Ratio · Lesson 3
Scale factors and scale drawings
Enlarge shapes by a scale factor, find scale factors, use map and drawing scales, and scale recipes up and down.
21-minute video lesson
Teaching, worked examples and 20 practice questions solved step by step.
Watch free for a monthWhat your child will learn
- Enlarge by a scale factor
- Find a scale factor
- Use map scales
- Use scale drawings
- Scale recipes
The method
- Find the multiplier.
- Multiply every length or amount.
- Going back? Divide.
- Convert units at the end.
Key words: scale factor, enlargement, scale, map, recipe.
Worked examples
The first three practice questions from the lesson, with every step.
Question 1
A rectangle is 2 cm by 1 cm. Enlarge it by scale factor 3. What are the new lengths?
- Step 1: Scale factor 3: multiply every length by 3
- Step 2: 2 × 3 = 6, 1 × 3 = 3
- Step 3: Draw it
Answer: 6 cm by 3 cm
Question 2
A rectangle is 4 cm by 3 cm. Enlarge it by scale factor 2. What are the new lengths?
- Step 1: Scale factor 2: multiply every length by 2
- Step 2: 4 × 2 = 8, 3 × 2 = 6
- Step 3: Draw it
Answer: 8 cm by 6 cm
Question 3
A rectangle is 5 cm by 2 cm. Enlarge it by scale factor 4. What are the new lengths?
- Step 1: Scale factor 4: multiply every length by 4
- Step 2: 5 × 4 = 20, 2 × 4 = 8
- Step 3: Draw it
Answer: 20 cm by 8 cm