Triangle Congruence: SAS, ASA, SSS vs. SSA Exploration

①This GeoGebra example dynamically demonstrates the three standard triangle congruence criteria (SAS, ASA, SSS) and the ambiguous SSA (side-side-non-included-angle) case, clarifying why SSA generally fails to guarantee congruence. ②Core mathematical concepts include triangle congruence, corresponding sides and angles, geometric construction, and counterexample reasoning. ③Construction details: using GeoGebra commands Segment, Circle, and Ray, the example builds points A', B', C' and segments a, b, c, d, e, allowing users to drag vertices and observe whether a unique triangle is determined under each condition. ④Suitable for middle school geometry, high school review, or teacher-education courses; ideal for classroom demonstration, student inquiry, or formative assessment to strengthen logical discrimination of congruence criteria.