Dilations of a Polygon: Interactive Geometric Transformation

① This interactive GeoGebra example demonstrates the dilation (scaling) of a triangle in the plane, showing how a polygon enlarges or shrinks relative to a fixed center. ② Core mathematical concepts include dilation center, scale factor, similarity, and collinearity of corresponding points, linking geometric transformation with proportional reasoning. ③ Construction highlights: using the Polygon command to define triangle ABC, with a slider or point controlling the scale factor; objects include vertices A, B, C, parameter t1, and sides c, a, b, allowing dynamic comparison between original and transformed shapes. ④ Suitable for middle school to high school students learning geometric transformations, and useful for teachers to visually explain dilation properties and coordinate changes in class.