Reflection in Pairs: Mirroring Polygons Across a Median Line

This GeoGebra activity demonstrates the reflection of a polygon (triangle) across a straight line, showing both the original and its mirror image simultaneously to visualize the geometric effect of axial symmetry. The core mathematical concepts include reflection (axial symmetry), special points such as midpoints, median lines, and properties of rhombi. The construction uses the Polygon command to create the original triangle, the Line command to define the reflection axis (median line), and the Mirror command to generate the reflected triangle across that line. Key objects include points A, B, C, the original polygon, the reflection axis (line c), and the reflected vertices A', B', C' with corresponding sides a', b', c'. This activity is suitable for middle or high school students learning geometric transformations, helping them understand distance preservation, symmetry, and the correspondence between original and reflected figures. It also serves as an introductory dynamic geometry exploration for teachers and learners.