论文部分内容阅读
人教版七年级下册“三角形”一章,第72页,“7.2.1三角形的内角”一节中的例1,是一道有多余条件的例题,多年来教材一直未做修改,笔者在执教该例题时,按如下的教学思路设计,取得了意想不到的收获.特将教学过程记录如下,与大家共享.【原例呈现】如图1,C岛在A岛的北偏东50°方向,B岛在A岛的北偏东80°方向,C岛在B岛的北偏西40°方向,从C岛看A、B两岛的视角∠ACB是多少度?
People’s Education Publishing House seventh grade under the book “Triangle ” chapter, page 72, “7.2.1 Triangle corner ” section 1, is an example of redundant conditions, the textbook has not been done for many years Modify, I coached the example, according to the following teaching ideas, has made an unexpected gain.Teaching process will be recorded as follows, to share with you. [The original example] As shown in Figure 1, C Island in A Island North East 50 ° direction, B Island in the north side of Island A 80 ° east direction, C Island B Island in the north west 40 ° direction, from C Island to see A, B island perspective ∠ ACB is how much?