Radius and Circumference Relationship

This interactive GeoGebra example explores the relationship between a circle's radius and its circumference. By adjusting a slider for the radius r, the built‑in Circumference command calculates the circumference c, which is displayed dynamically using the Textc object. The activity illustrates the fundamental formula C = 2πr, highlighting the linear proportionality and the role of π, and it reinforces concepts of geometric measurement, variable dependence, and dynamic visualization. It is designed for middle‑school and high‑school students learning geometry, algebra, and the use of computational tools in mathematics.