Exploration of Vertical and Adjacent Supplementary Angles

This applet demonstrates the properties of vertical angles and adjacent supplementary angles, aligning with the Grade 7 mathematics curriculum. Using GeoGebra dynamic geometry, the applet visually illustrates that when two straight lines intersect, the vertical angles formed are equal in measure, and adjacent supplementary angles sum to exactly 180 degrees. Students can drag the intersection point or any point along the lines to dynamically observe how the angles change while maintaining these fundamental relationships. This interactive exploration helps learners develop an intuitive and rigorous understanding of intersecting lines, the definition and properties of vertical angles, and the concept of adjacent supplementary angles. By manipulating the figure in real time, students can verify that angle equality and angle sum properties hold regardless of the configuration, reinforcing both geometric reasoning and angle calculation skills. The applet serves as an effective visual and hands-on tool for classroom instruction, allowing teachers to guide students through discovery-based learning and helping them internalize the core properties of angle pairs formed by intersecting lines.