Same Side Interior Angles Theorem: Dynamic GeoGebra Demonstration

This GeoGebra example dynamically demonstrates the Same Side Interior Angles Theorem, which states that when two parallel lines are cut by a transversal, the same-side interior angles are supplementary (sum to 180°). The construction involves core geometric concepts such as parallel lines, transversals, interior angles, supplementary angles, and angle measurement. Using GeoGebra commands including Point, Line, Angle, Circle, Intersect, Rotate, Dilate, Vector, Translate, and CircleArc, the applet constructs lines, intersection points, angle markers, circles, and arcs, with dynamic elements (sliders or draggable points) that allow users to change the transversal's position and observe that the sum of the two same-side interior angles remains constant at 180°. This resource is ideal for middle school or high school geometry classes, helping students visualize and verify the theorem, and for teachers creating interactive lessons or exploratory activities.