Same Side Exterior Angles Demonstration

① This example visually demonstrates the same-side exterior angles (a pair of angles lying on the same side of the transversal and outside the two intersected lines) formed when two lines are cut by a transversal. ② The core mathematical concept is the theorem of same-side exterior angles in parallel lines: if two lines are parallel, then same-side exterior angles are supplementary; conversely, if same-side exterior angles are supplementary, then the lines are parallel. ③ Construction details: using GeoGebra commands Line to create three lines (objects f, g, h), Intersect to obtain intersection points (A, B, C, D, etc.), Point to mark key points, and Angle to create angles α and β; a button (button1) is included for interactive control, possibly to toggle parallel status or display angle measures. ④ Suitable for middle school geometry or introductory high school analytic geometry, helping students intuitively understand angle relationships formed by a transversal cutting parallel lines, and can serve as a dynamic geometry exploration resource by dragging lines or using the button to observe angle changes.