Myths about teaching can hold you back
- Year 8
Circumference of a circle
I can use the relationship C=πd to calculate unknown lengths in contexts involving the circumference of circles.
- Year 8
Circumference of a circle
I can use the relationship C=πd to calculate unknown lengths in contexts involving the circumference of circles.
Lesson details
Key learning points
- The formula can be used to find the circumference when you know the diameter.
- The formula can be used to find the circumference when you know the radius.
- The formula can be used to find the radius or diameter when you know the circumference.
- These answers will be rounded to an appropriate degree of accuracy.
- For the answer to be exact it needs to be left in terms of π.
Keywords
Circumference - The circumference of a circle is the perimeter of the circle.
Radius - The radius of a circle is any line segment that joins the centre of a circle to its edge.
Diameter - The diameter of a circle is any line segment that starts and ends on the edge of the circle and passes through the centre.
Common misconception
When writing answers in terms of π, pupils may think that π is the units.
π is a constant and makes up part of the numerical component of the answer. Units (such as square metres) still need to be stated.
To help you plan your year 8 maths lesson on: Circumference of a circle, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 8 maths lesson on: Circumference of a circle, 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 3 maths lessons from the Perimeter, area and volume unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Prior knowledge starter quiz
6 Questions
Q1.Which part of the circle is labelled?

Q2.If a circle has a diameter of 12 cm then its radius will be cm.
Q3.$$\pi$$ is the ratio between which two parts of a circle?
Q4.Which two formulae can be used to calculate the circumference of a circle?
Q5.A circle with diameter 12 cm has a circumference of cm.
Q6.A circle with radius 20 cm has a circumference of cm.
Assessment exit quiz
6 Questions
Q1.Which part of the circle is labelled?

Q2.A circle with a diameter of 6 cm has a circumference of cm, when rounded to 1 decimal place.
Q3.The circumference of the circle is cm, when rounded to 3 significant figures.
