# Circle as a shape

A circle is the set of all points in the plane that are a fixed distance from a fixed point.

### Objectives

Understanding circle as a shape

30 minutes

### Prerequisites/Instructions, prior preparations, if any

Prior knowledge of point, lines, angles, polygons

### Materials/ Resources needed

• Digital : Computer, geogebra application, projector.
• Non digital : Worksheet and pencil
• Geogebra files : Introduction to circles.ggb

### Process (How to do the activity)

• Draw circle with ‘circle with center and point’ or use the slider
• What do you notice, how is the circle formed.
• Which point is the centre of the circle ?
• Plotting points on the circle, connect these points to the centre of the circle.
• What can you say about the segment lengths?
• Measure the segment lengths to show they are equal.
• Establish center of the circle’ and ‘radius’
• Differentiate between circle and region enclosed by a circle.
• Evaluation:
1. By what parameter is the size of a circle defined ?