Year 8

Area of a Circle

Students investigate different demonstrations for the formula for the area of a circle.

This is a classic reSolve sequence aligned with the Australian Curriculum V8.4. It is only available as a downloadable package.

Students use their knowledge of the relationship between the circumference and diameter of a circle to see why the area of a circle is πr2. Guiding questions encourage students to think about issues of accuracy and informally introduce the idea of the circle as a limiting shape. The lesson involves visualisation and explanation.

This sequence is for students who:

• know basic properties of circles.
• know the formulas for the circumference of a circle and the area of a triangle.
• are familiar with π as the ratio of circumference to diameter of a circle.

Lesson 1: Four Demonstrations

Students work in groups to understand one of four demonstrations of the formula A = πr2 and explain to others why the formula works. In the process, they refine both their own understanding and their explanations.

Last updated June 21 2020.

This is a classic reSolve sequence aligned with the Australian Curriculum V8.4. It is only available as a downloadable package.