Area and Circumference of a circle (Years 7-9)
A collection of resoures for 2-3 lessons at Key Stage 3 level, introducing area and circumference of a circle with a focus on pi, its value and significance.
Lesson 1: Ask pupils to bring to class a selection of circular objects, from cellotape to mugs. Using the lesson idea from "Shape, Space and Measures 3" (page 78 on the PDF), allow pupils to explore the connection between the two properties, encouraging them to come up with a formula as you go. You can choose to show them the table and fill in some of their own or to allow them to investigate from scratch. The "KS3 Maths - Introducing Pi" video from Teacher's TV demonstrates how this lesson should work. After Pi has been introduced, you could finish with a round of "Pi Dingbats".
Lesson 2: Follow the link to "Area of a Circle". There is a lot of information here but on page 3 of the PDF there is a great idea. Have pupils cut 4 different radius squares from different coloured card. Then stick them into a circle which has the same radius as the length of the squares. They should be able to fit just over 3 squares in, leading to a discussion about the importance of pi and the formula pi * r^2.
Lesson 3: An investigation that uses the knowledge from lesson 1 to explore how to create an accurate running track. All resources are included within. If you have a running track, take the class out to see it and compare their ideas with what it should look like.
Links and Resources
A booklet containing many ideas and questions for Shape topics at Key Stage 3.
Pupils explore how to draw a perfect running track using their knowledge of th circumference of a circle.