能够完全重合的两个三角形叫做全等三角形,实质上就是这两个三角形的三对对应角,三对对应边分别相等,共有六个相等关系.用△ABC≌△A′B′C′表示两个三角形全等,就表示上述六个相等关系同时成立.对这两个全等三角形当然要把对应顶点的字母分别写在对应位置:A和A′,B和B′,C和C′分别对应,不可写乱.把彼此全等的三角形归于一类,有了判定两 The two triangles that can be completely coincident are called congruent triangles. In essence, they are the three pairs of corresponding angles of the two triangles. The three pairs of corresponding sides are respectively equal, and there are six equal relations. They are represented by ΔABC≌ΔA′B′C′. The two triangles are congruent and mean that the above six equal relations are established at the same time. For the two congruent triangles, of course, the letters of the corresponding vertices should be written in the corresponding positions: A and A’, B and B’, C and C’ respectively. Correspondence respectively, can not be confused. Concatenate the triangles to one another and have two