Supplementary Angles: Interactive Geometric Construction

This GeoGebra applet demonstrates supplementary angles—two angles whose measures sum to 180 degrees, forming a straight angle. The core mathematical concepts include angle measurement, supplementary angle pairs, straight angles, adjacent angles, and the geometric relationship between rays and lines. The construction is built using GeoGebra commands Line, Point, Rotate, Angle, and Ray, producing objects such as points A, B, C, D, lines a and b, rays, and angles α, β, γ. By applying rotation and dynamic manipulation, learners can visually verify that the constructed angles are supplementary. This resource is ideal for middle school and early high school geometry instruction, teacher-led classroom demonstrations, and independent student exploration of angle relationships.