Calculate the side length of a regular polygon by division where the perimeter is known
Lesson details
Learning outcome
I can use division to calculate the side length of a regular polygon when the perimeter is known.
Key learning points
- If you know the perimeter of a regular polygon you can calculate the length of one side.
- Divide the perimeter by the number of sides to calculate the length of one side.
- Knowledge of times tables and related division facts can support calculation.
Keywords
Perimeter - The distance around a two-dimensional shape.
Regular - A regular polygon has all sides equal and all angles equal.
Common misconception
Pupils often find division a trickier concept than multiplication and do not connect this to their known multiplication facts.
Establish the inverse relationship with multiplication and show how the division equations can be re-written as a multiplication equation with a missing factor. Support pupils in making this connection to allow them to use known facts to calculate.
Teacher tip
Known multiplication facts are key in this lesson and pupils should be increasingly fluent in tables learned in Years 2 and 3. Multiplication grids may be a useful scaffold for less confident pupils.
Licence
except where otherwise stated. See Oak's terms & conditions (Collection 2).Lesson video
Loading...
Prior knowledge starter quiz
6 Questions
Q1.Select all of the squares.
Q2.What is the perimeter of a square with a side length of 5 cm? cm.
Q3.What is the perimeter of a regular triangle with a side length of 5 cm? cm.
Q4.What is the perimeter of a regular pentagon with a side length of 5 cm? cm.
Q5.Lucas is trying to work out 20 ÷ 5 but he is struggling. How else might he think of this question?
Q6.Order these shapes from smallest perimeter to longest.
Assessment exit quiz
6 Questions
Q1.If you know the perimeter of a regular polygon, what can you do to find the length of each side?
Q2.What is the side length of a square with a perimeter of 16 cm?
Q3.Lucas has measured the perimeter of his classroom, which is square-shaped. Its perimeter is 24 metres. What is the length of one side of the classroom? m.
Q4.What is the side length of a regular triangle with a perimeter of 15 cm? cm.
Q5.What is the side length of a regular five-sided shape with a perimeter of 30 cm? cm
Q6.What is the side length of a regular five-sided shape with a perimeter of 300 cm? cm.
To help you plan your 4 maths lesson on: Calculate the side length of a regular polygon by division where the perimeter is known, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 4 maths lesson on: Calculate the side length of a regular polygon by division where the perimeter is known, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 2 maths lessons from the Perimeter unit, dive into the full primary maths curriculum, or learn more about lesson planning.