New
New
Year 6

# Identify and describe the relationship between irregular polygons using scale factors

You can identify and describe the relationship between two irregular polygons using scale factors

New
New
Year 6

# Identify and describe the relationship between irregular polygons using scale factors

You can identify and describe the relationship between two irregular polygons using scale factors

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## Lesson details

### Key learning points

1. Two similar shapes can be described as being 'x' times greater or smaller than each other.
2. If one similar shape is smaller than another, the scale factor is a fraction.
3. Shapes related by a scale factor are similar.

### Common misconception

Not comparing the same or corresponding sides of related shapes.

Label the sides of shapes clearly and refer to them with consistent language of height and width.

### Keywords

• Irregular polygon - An irregular polygon is a polygon where the sides and angles are not all equal

Make sure that pupils have the opportunity to explain what is happening as the shapes are scaled and that all dimensions are being multiplied by the same scale factor.
Teacher tip

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Starter quiz

### 6 Questions

Q1.
Correct answer: Length of sides 6 cm
Area is 36 squared cm
Opposite sides are parallel
Angles are right angles
Q2.
Which of these pairs of shapes are similar?
B
A and B
Neither A or B
Q3.
What is the scale factor between hexagons A and B?
2
3
4
8
Q4.
What number is one and a half times the size of 6?
3
6
12
Q5.
Which of these shapes is similar to triangle A with a scale factor of 4?
Correct Answer: An image in a quiz
Q6.
Which of these shapes is similar to square A with a scale factor of one half?
Correct Answer: An image in a quiz

## Exit quiz

### 6 Questions

Q1.
Which of these shapes are regular polygons?
rectangle
trapezium
right angled triange
Q2.
Which of these shapes are irregular polygons
equilateral triangles
square
Q3.
Is a hexagon a regular shape?
Yes
No
Correct answer: Yes if all its sides are the same length
Q4.
A and B are similar rectangles. What is the missing dimension in rectangle B?
15 cm
40 cm
20 cm