Coordinate Rules for Reflections - Mirroring a Scalene Triangle

① This example demonstrates how the coordinates of a scalene triangle change under a reflection (mirror) transformation in the Cartesian plane, visually illustrating the coordinate rules for reflections. ② The core mathematical concepts include reflection (axial symmetry) in plane geometry, coordinate transformation rules (e.g., sign changes for reflections across the x-axis, y-axis, or a given line), and properties of triangles and polygons. ③ Construction highlights: Based on the construction summary, GeoGebra commands such as Intersect and Polygon are used, creating objects A, B, E, D, C, polygon poly1, and sides a, c, d, e, b, which together form the original triangle and its reflected image for easy comparison of corresponding coordinates. ④ This is suitable for middle or high school students learning plane geometry transformations and introductory coordinate geometry, as well as for teachers demonstrating reflection coordinate rules in class to help students grasp the connection between symmetry and coordinate operations.