小学教育网 发表于 2018-10-14 21:41:36

北京版六年级数学上册教案设计《扇形》

北京版六年级数学上册教案设计《扇形》
          教学目标:
       
          1、学生结合生活的物品,认识扇形,掌握扇形的各部分名称。
       
          2、通过动手操作、实验观察,探索出扇形的大小与圆心角的大小有关。
       
          教学重点:
       
          在动手操作中掌握扇形的特征。
       
          教学难点:
       
          理解扇形的大小与圆心角的关系。
       
          教学准备:
       
          扇形实物
       
          教学过程:
       
          一、复习导入
       
          1.有一根绳子长31.4m,小红、小东和小林分别想用这根绳子在操场上围出一块地,怎样围面积最大?
       
          北京版六年级上册数学《扇形》教案
       
          二、创设情景,生成问题
       
          1、出示第75页主题图,谈话
       
          (1)主题图上呈现的是什么?
       
          (2)这些物体的名称都含有“扇”字,那什么是扇形呢?
       
          (3)根据画面情境,你能说出一些扇形的物体吗?
       
          2、揭示课题:在我们日常生活中,有很多扇形的物体,今天我们就来研究扇形。
       
          3、板书课题:认识扇形

jzthree 发表于 2018-10-14 22:03:08


          三、探索交流,解决问题
       
          1、认识扇形的各部分名称。
       
          (1)介绍扇形的含义:一条弧和经过这条弧两端的两条半径所围成的图形叫做扇形。
       
          (2)介绍扇形各部分的名称
       
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
       
          弧:圆上A、B两点之间的部分叫做弧。
       
          圆心角:像<AOB这样,顶点在圆心的角叫做圆心角。
       
          (3)观察:在同一个圆中出现不同圆心角的扇形,你发现了什么?
       
          (4)结论:扇形的大小与这个扇形的圆心角的大小有关
       
          2、认识特殊的扇形
       
          (1)以半圆为弧的扇形的圆心角是多少度?
       
          学生自主探索:半圆的圆心角是180°
       
          (2)以1/4圆为弧的扇形呢?
       
          1/4圆:圆心角是90°
       
          四、巩固应用,内化提高
       
          1、完成第76页第1题。
       
          根据扇形的含义,找一找物体中的扇形。
       
          2、完成第76页第2题。
       
          圆心角一定是两条半径组成的角。
       
          3、完成76页第3题
       
          把画圆和画角结合起来,培养学生作图能力。
       
          4、完成76页第4题
       
          介绍扇环知识。扇环就是圆环的一部分,求圆环面积的方法迁移到这,求扇环的面积
       
          五、回顾整理,反思提升
       
          这节课你收获了什么?
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