Reflection Activity 7: Triangle Mirror Transformation

①This example demonstrates the reflection (mirror) transformation of a triangle about a coordinate axis (x-axis or y-axis), dynamically showing the relationship between the original triangle and its reflected image. ②Core mathematical concepts include axial symmetry (reflection) in plane geometry, involving symmetry properties, perpendicular bisectors of corresponding point segments, and sign changes in vertex coordinates. ③Construction details: The Polygon command creates the original triangle; If and Vector commands define reflection vectors; Textfield input boxes control the visibility of the reflection axis (x-axis or y-axis); the reflected triangle and its vertices (A', B', C') are generated, along with arrows and text labels. ④Suitable for middle school geometry lessons, this interactive tool helps students intuitively grasp properties of reflection, such as congruence and orientation reversal, and can be used as a dynamic exploration activity.