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      Identify and describe the relationship between regular polygons using scale factors

      Lesson details

      Learning outcome

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

      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.

      Keywords

      • 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

      Common misconception

      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.

      Teacher tip

      Make sure that pupils are aware that it is the lengths of the sides of the shapes, the dimensions, that are scaled and that the scale factors apply to those and not to the area which is covered in future learning.

      Licence

      This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0
      except where otherwise stated. See Oak's terms & conditions
      (Collection 2).

      Lesson video

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      Prior knowledge starter quiz

      6 Questions

      Q1.
      What number is 11 times greater than 5?

      Correct Answer: 55, fifty five, fifty-five

      Q2.
      What number is one half times the size of 72?

      34
      35
      Correct answer: 36
      37

      Q3.
      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?

      An image in a quiz
      31
      20
      Correct answer: 11
      3

      Q4.
      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?

      An image in a quiz
      Correct Answer: 24, twenty four, twenty-four

      Q5.
      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?

      An image in a quiz
      $$63 - 7 = 56$$
      Correct answer: $$63 \div 7 = 9$$
      $$7 \times 7 = 49$$
      $$3 + 4 = 7$$

      Q6.
      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?

      An image in a quiz
      60
      59
      49
      Correct answer: 36

      6 Questions

      Q1.
      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
      Correct answer: The length of the sides and edges of a 2D shape
      The properties of a 2D shape

      Q2.
      Write the 2 words which complete this definition of a regular polygon: A regular polygon has all ___ the same length and all ___ equal.

      areas
      Correct answer: sides
      properties
      Correct answer: angles

      Q3.
      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
      Correct answer: ... the ratio between the dimensions of the original shape and a new shape
      Correct answer: ... number you multiply each dimension by to create a similar polygon

      Q4.
      What is the scale factor between triangles A and B?

      An image in a quiz
      8
      4
      Correct answer: 3
      16

      Q5.
      Sam says that the scale factor between triangles A and B is 12. Are they correct?

      An image in a quiz
      Yes
      Correct answer: No

      Q6.
      Sam says that the scale factor between triangles A and B is 12. Why is Sam not correct?

      An image in a quiz
      Correct answer: Sam has calculated the difference between the length of a side of each triangle
      Correct answer: Sam has not worked out how many times longer the length of a side in B is
      Correct answer: Sam has not worked out how many 3s there are in 15
      Correct answer: Sam has not thought about multiplication and division

      To help you plan your 6 maths lesson on: Identify and describe the relationship between regular polygons using scale factors, download all teaching resources for free and adapt to suit your pupils' needs...