Visual Proof of Cosine Rule: Geometric Diagram

This example demonstrates how to visually prove the Cosine Rule through geometric construction. It creates a visualization showing c²=a²+b²-2ab·cosθ using triangles, rays, circles, and polygons with intersecting lines, angle markers, and segment relationships. The construction uses GeoGebra commands: Point, Ray, Circle, Intersect, Segment, Line, Angle, Polygon, with adjustable parameter θ for dynamic demonstration. Ideal for middle and high school math teachers teaching trigonometry or geometric proofs, and for students exploring the geometric meaning of the Cosine Rule.