已知:在△ABC和△A'B'C'中,AB=A'B', AC=A'C'.AD,A'D'分别是△ABC和△A'B'C'的中线,且AD=A'D'.
求证:△ABC≌△A'B'C'
证明:分别过B,B'点作BE‖AC,B'E'‖A'C'.交AD,A'D'的延长线于E,E'点.
则:△ADC≌△EDB, △A'D'C'≌△E'D'B'
所以:AC=EB,A'C'=E'B'; AD=DE, A'D'=D'E'.
所以:BE=B'E', AE=A'E'
所以:△ABE≌△A'B'E'
所以:角E=∠E' 角BAD=角B'A'D'
所以:角BAC=角B'A'C'
所以:△ABC≌△A'B'C'
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