Know and use the formulae for the area and circumference of a circle

Examples of what pupils should know and be able to do

Probing questions

  • What is the minimum information you need to be able to find the circumference and area of a circle?
  • Give pupils some work that includes mistakes.
  • Ask them to identify and correct the mistakes.
  • How would you go about finding the area of a circle if you knew the circumference?

What if pupils find this a barrier?

Ensure that pupils understand that Π is the ratio of the length of the circumference of a circle to its diameter.

Demonstrate an approximation to the area by cutting a circle into 16 sectors and forming an approximation to a rectangle to establish a visual approximation to πr2.

Ensure that πr2 is seen as π×r×r.

Give pupils some work that includes mistakes and ask them to correct them. Be specific about common mistakes.