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人与人相遇是缘,人与题目相遇也是缘.偶有学生来问:如何找出三种方法将正三角形切割为4个等腰三角形?师生讨论出的答案如下:前两种方法一目了然(但解读有多种).第三种却不易一眼发现水平线的具体位置.需申明水平切割线是过几何对称中心.作为求教者,学生已经释然.作为老师却感觉有必要继续引申一番.于是追问:如果题目改为“找出将一个等腰三角形切割为
Encounter between people is the edge, people and the subject is the edge encounter. Occasionally students to ask: How to find three ways to cut the equilateral triangle isosceles triangle? Teachers and students discussed the answer is as follows: The first two methods at a glance (But a variety of interpretation.) The third is not easy to find the specific location of the horizontal line. Be sure to declare the horizontal cutting line is over the geometric center of symmetry as a church-seeker, the students have relieved as a teacher felt it necessary to continue to extend it. Then ask: if the subject is changed to ”find out to cut an isosceles triangle