Identify and describe the relationship between regular polygons using scale factors | Maths

Starter quiz

What number is 11 times greater than 5?

'55' ✓
What number is one half times the size of 72?

34

35

36 ✓

37
Sam makes lemonade and uses 1 part lemon for every 3 parts water. If they use 33 parts water, how many parts of lemon will they need?

31

20

11 ✓

3
Sam makes lemonade and uses 1 part lemon for every 3 parts water. If they use 8 parts lemon, how many parts of water will they need?

'24' ✓
A quiz team is made up of 3 adults and 4 children. If there are 63 people taking part. Which equation represents the number of teams taking part?

$63 - 7 = 56$

$63 \div 7 = 9$ ✓

$7 \times 7 = 49$

$3 + 4 = 7$
A quiz team is made up of 3 adults and 4 children. If there are 63 people taking part, how many of them are children?

60

59

49

36 ✓

Which of these statements describe the dimensions of a 2D shape

The sizes of the angles of a 2D shape

The area of a 2D shape

The length of the sides and edges of a 2D shape ✓

The properties of a 2D shape
Write the 2 words which complete this definition of a regular polygon: A regular polygon has all ___ the same length and all ___ equal.

areas

sides ✓

properties

angles ✓
Which phrase completes this sentence: A scale factor is ___.

... the sum of the lengths of the sides of a polygon

... the number of sides a polygon has

... the ratio between the dimensions of the original shape and a new shape ✓

... number you multiply each dimension by to create a similar polygon ✓
What is the scale factor between triangles A and B?

8

4

3 ✓

16
Sam says that the scale factor between triangles A and B is 12. Are they correct?

Yes

No ✓
Sam says that the scale factor between triangles A and B is 12. Why is Sam not correct?

Sam has calculated the difference between the length of a side of each triangle ✓

Sam has not worked out how many times longer the length of a side in B is ✓

Sam has not worked out how many 3s there are in 15 ✓

Sam has not thought about multiplication and division ✓

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

That regular polygons include all familiar shapes even if they don't meet the definition.

Reinforce the definition and apply to the regular shapes which appear in this lesson.

Dimensions - The dimensions of an object or shape are the lengths of its sides and edges
Scale factor - A scale factor is the ratio between the dimensions of the original shape and the new shape. The scale factor can be an integer or a fraction
Regular polygon - A regular polygon has all sides the same length and all angles equal
Similar shapes - Similar shapes can be transformed into each other by scaling their dimensions by the same scale factor