Circle Area and Circumference Demonstration

This example demonstrates how the area and circumference of a circle change as the radius varies. Key math concepts include circle area formula, circumference formula, and variable relationships. It uses GeoGebra commands like Circle, Area, Circumference, and objects such as r (radius), A (area), c (circumference), Textc, areac, circumferencec, and text elements. Suitable for middle school and above students to learn basic circle properties and formula applications, or for mathematical demonstrations.