人教版数学七年级上角课件.ppt

复习回顾: 1、什么叫射线? 2、由一点为端点能画几条射线? 3、如何表示射线? 直线上的一点和它一旁的部分叫做射线。如图· O· A 无数条。· 一条射线用端点和射线上另一点来表示,或用一个小写字母来表示。 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 角(1) 石堰中学教研组 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 学习目标学习目标 1. ,理解角的形成, 通过丰富的实例,理解角的形成, 建立几何中角的概念。建立几何中角的概念。 2. 。方法。 3. ,理解平角、周角的结合实际例子,理解平角、周角的概念。概念。 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 看课本 p136 —137 内容回答: , 角有两种定义,说说看. 2. 怎样来表示一个角?三种表示方法都适用于每一个角吗? Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 角是由两条具有公共端点的射线组成的图形。公共端点顶点射线射线边边 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 角也可以看做一条射线绕端点旋转所组成的图形。(角的旋转定义) Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. o A B∠ AOB 是平角特点:两边在同一条直线上。· 返回 Evaluation only. Evaluation only. Created with Client Profile . Created with Clie