Step 8 Objective

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.