Reflection Triangle: Reflecting a Point Across Triangle Sides

① This example demonstrates how to reflect a free point P across each side of a given triangle ABC, producing three reflected points that form the vertices of a 'reflection triangle'. ② The core mathematical concept is axial symmetry (mirror reflection), where each reflected point is the mirror image of P with respect to the line containing a side; it also involves triangle geometry, polygon construction, and area relationships. ③ Construction highlights: using GeoGebra commands Polygon to create triangle ABC, Segment to draw its sides, and Mirror to reflect point P across each side, yielding three reflected points (P', P'_1, P'_2); these are then connected to form the reflection triangle, with text objects displaying labels or measurements. ④ Suitable for middle and high school geometry classes, this interactive example helps students visualize reflection transformations, explore symmetry properties, and observe how the reflection triangle changes as P is dragged dynamically, making it ideal for hands-on exploration of geometric transformations and area comparisons.