Cyclic Quadrilateral Demo

This example demonstrates the property that if a line segment joining two points subtends equal angles at two other points lying on the same side of the line containing the line segment, then the four points are concyclic. It involves core mathematical concepts such as circle, angle, triangle, and concyclic points. Construction highlights include using GeoGebra commands like Intersect, Circle, Point, Segment, and Angle. Suitable for high school geometry education and learning.