已知,△ABC ≌ △A'B'C' ,AD和A'D'分别是两个三角形的中线,求证：AD = A'D' .证明：已知,△ABC ≌ △A'B'C' ,可得：AB = A'B' ,BC = B'C' ,∠ABC = ∠A'B'C' .在△ABD和△A'B'D'中,AB = A'B' ,∠ABC = ∠A'B'C' ,BD ...