一、问题的提出2011年上海中考卷中有这样一道试题:下列命题中,真命题是()(A)周长相等的锐角三角形都全等(B)周长相等的直角三角形都全等(C)周长相等的钝角三角形都全等(D)周长相等的等腰直角三角形都全等该题并不难,因为多数学生知道“全等三角形的周长相等,但周长相等的三角形不一定全等”这一事实.然而,这道中考题却诱发我们思考这样一个问题:全等三角形判定定理中能否融入“三角形周长相等”这一条件? First, the question raised in Shanghai in 2011 test papers have such a test: the following proposition, the true proposition is (A) equal perimeter acute triangles are congruent (B) equal length of right-angle triangles are equal C) Obtuse triangles of equal circumference are congruent (D) Equal isosceles right triangles of equal circumference are equal, because most students know that “congruent triangles have equal perimeters but equal perimeters Triangle is not necessarily congruent. ”However, this middle school entrance exam questions us to think about the question of whether the congruent triangle theorem can fit into the condition that the“ triangle circumference is equal ”.