Myths about teaching can hold you back
- Year 8
Using the formula for the area of a circle
I can use the formula for the area of a circle to calculate either the area or a missing measurement.
- Year 8
Using the formula for the area of a circle
I can use the formula for the area of a circle to calculate either the area or a missing measurement.
Lesson details
Key learning points
- The area of any circle can be found if the radius is known.
- The radius can be calculated from the diameter.
- The area of a circle can be used to calculate the radius .
- The area of a circle can be used to calculate the diameter.
- For the answer to be exact it needs to be left in terms of π.
Keywords
Area - Area is the size of the surface and states the number of unit squares needed to completely cover that surface.
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 calculating the diameter, pupils may use rounded numbers to perform subsequent calculations.
Repeat one of the demonstrations of finding the diameter but round each decimal as they appear and compare the accuracy of the final answer.
To help you plan your year 8 maths lesson on: Using the formula for the area 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: Using the formula for the area 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
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Match the parts of a circle with their descriptions.
circumference -
the distance around the edge of a circle
diameter -
furthest distance from one side of a circle to the other
radius -
any line segment from centre to circumference of circle
Q2.What is 10$$\pi$$ as a decimal rounded to 3 significant figures?
Q3.Evaluate the expression $$5x^2$$ when $$x=2$$.
Q4.Solve the equation: $$4x^2 = 36$$
Q5.Which is the formula for the area of a circle?
Q6.What is the area of the circle?

Assessment exit quiz
6 Questions
Q1.The area of a circle can be calculated by multiplying $$\pi $$ by the square of the .
Q2.A circle has radius 10 cm. Its area is cm$$^2$$, when rounded to 3 significant figures.
Q3.The area of the circle is cm$$^2$$.
