究竟有几条对称轴

• 作 者: 李志荣
• 机 构: 安徽省霍邱县宋点乡八里小学,
• 出 处: 中小学数学(小学版)
• 发表日期: 2016年12期
• 关键词: 轴对称图形 操作题 图形的 外部轮廓 数学图形 平面图形 标识点 毫不示弱 资深教师 建筑雕塑

在教学“圆的认识”时,我与学生在试卷上遇到下面这道题(图1)。画出下面图形的所有对称轴。这是一道操作题,学生在答卷的时候,主要出现两种做法:一种做法是在图上画2条对称轴,横着、竖着各有1条(图2);另一种做法是只在图上画1条对称轴(图3)。在批阅试卷前,我征求了办公室里多数同事的意见。他们也不约而同的分成两种观点。赞成有2条对称轴的老师认为:轴对称图形的定义说得很清楚,“只

I encountered the following question on the paper with the students when teaching ”Circle of Understanding“ (Figure 1). Draw all the symmetry axes of the following graphic. This is a question of operation. When answering a questionnaire, students mainly come up with two approaches: one is to draw two symmetrical axes on the graph, one horizontally and one vertically (Figure 2); the other is only Draw 1 axis of symmetry on the drawing (Figure 3). Before I got the papers, I consulted most of my colleagues in the office. They also spontaneously divided into two perspectives. In favor of a teacher with two symmetry axes, the definition of axisymmetric graphics makes it very clear that ”only