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1、学习好资料欢迎下载新人教版小学数学四年级下册三角形的内角和教学设计教学内容：（人教版）小学数学四年级下册 三角形中三角形的内角和（书第 67、68 页）。教学目标：1、知识技能目标：（1）理解和掌握三角形的内角和是180；（2）运用三角形的内角和知识解决实际问题和拓展性问题；2、能力技能目标：（1）通过测量、撕拼、折叠等方法，探索和发现三角形三个内角的和等于 180。（2）知道三角形两个角的度数，能求出第三个角的度数。（3）发展学生动手操作、观察比较和抽象概括的能力。3、情感与态度目标：让学生体验数学活动的探索乐趣，通过教学中的活动体会数学的转化思想。教学重难点重点：理解掌握三角形的内角和是1
2、80。难点：运用三角形的内角和知识解决实际问题。教具、学具准备：教具：教学课件、硬纸片制作的各种三角形、三角尺。学习好资料欢迎下载学具：直角三角形、锐角三角形和钝角三角形各一个,量角器、两个三角板。一、创设情境生成问题（一）课件出示三角形争吵图在数学王国里住着很多平面图形。一天三角形兄弟忽然吵了起来，直角三角形说我的个头最大所以我的内角和一定最大，钝角三角形说我有一个钝角所以我的内角和一定比你们的大，只有锐角三角形很没自信的说：难道只有我的内角和最小？（二）猜想什么是三角形的内角和师：他们三个在比什么呀?什么是三角形的内角？什么是三角形的内角和？课件演示三角形的内角（内角和）二、探索交流解决问
3、题（一）猜想内角和的度数师：同学们你当小裁判来评一评他们三个谁的内角和最大？生：我认为他们的内角和一样大都是180 度。生 2：我也这认为他们的内角和一样大。师：还有不同意见吗？看来裁判们一致认为他们三个的内角和一样大都是180 度可是他们三个听了咱们的话以后吵得更凶了，因为他们三个谁都不相信三角形的内角和都是180 度，同学们要想当好一个裁判除了要公平公正还要有足够的证据，怎样才能让他们三个心服口服？你有想办法来验证三角形的内角和是180 度吗？板书文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2
4、A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1
5、D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2
6、A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1
7、D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2
8、A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1
9、D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2
10、A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2学习好资料欢迎下载课题：三角形的内角和（二）讨论验证方法以小组为单位来想一想我们可以怎么样来验证？小组活动后汇报（三）动手验证生活动师巡视（四）汇报师：哪个小组来汇报你们的验证方法和验证结论？刚才呼声最高的是度量的方法哪个小组用了度量的方法？生回答。（回答可能不一样。）师：同学们通过刚才的汇报你有什么想说的吗？生：我发现内角和的度数不一样。师：是啊什么原因？生：可能是量的时候出现了差错。师：是的，在度量时由于测量的误差很容易导致最后的结果出现差错，同学们有没有更精确地验证方法？组 1：我们用的是撕的
11、方法，把锐角三角形的三个角都撕下来，然后拼在一起就拼成了一个钝角。结论是锐角三角形的内角和是180度。师：这个小组很厉害，运用了平角的知识来验证的。哪个小组也用了这种撕拼的方法？组 2：我们也是用撕拼的方法验证了钝角三角形的内角和是180文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M
12、8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文
13、档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M
14、8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文
15、档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M
16、8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文
17、档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2学习好资料欢迎下载度。组 3：我们用这种撕拼的方法验证直角三角形的内角和也是180度。哪个小组的同学最想上来展示一下你们的
18、研究成果？师：同学们做得很好，看来用剪拼的方法验证了三角形的内角和确实是 180 度。老师也用剪拼的方法来验证三角形的内角和，同学们想不想看？(动画演示剪拼验证过程)边演示边解说。见证奇迹的时刻到了，你发现了什么？同学们还有不同的验证方法吗？组:我们用的是折一折的方法，把锐角三角形的三个内角向里折，也拼成了一个平角，结论：锐角三角形的内角和是180度。组：:我们用的是折一折的方法，把钝角三角形的三个内角向里折，也拼成了一个平角，结论：钝角三角形的内角和是180 度。出示：普通折法师：还有不同折法吗？组：我们还可以这样折，把直角三角形的内角向里折。把直角三角形的两个锐角转化成一个直角。这样验证出
19、：直角三角形的内角和是 180.度。师：恩很独特的方法，不但验证除了内角和还知道了直角三角形的两个锐角之和是90 度。文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文
20、档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M
21、8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文
22、档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M
23、8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文
24、档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M
25、8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2学习好资料欢迎下载课件演示独特折法师：刚才有几个小组完成的很快所以老师又送了他们几个长方形。看到长方形你们想到了什么？你们能根据手里的长方形想出其他方法验证三角形的内角和是180 度吗？组：我们认为一个长方形的内角和是360 度，把他沿着对角
26、线撕开就得到了两个完全一样的直角三角形，360除以 2 等于 180 度。结论直角三角形的内角和是180度。是不是两个完全一样的三角形都能拼成一个长方形？课件演示长方形推理法。师：刚才我们用已知的长方形的内角和验证了直角三角形的内角和是 180度。看来当我们遇见一个新问题时可以联想一下以前学过的知识，这样新问题就会很快解决，这种转化法是学习数学的一种很重要的方法希望同学们以后大胆应用。那现在我们能不能用“直角三角形的内角和是 180 度”这个结论来验证锐角三角形、钝角三角形的内角和是 180 度呢？在黑板上画任意一个锐角三角形。谁能把它分成 2 个直角三角形呢？抽生上台分。能不能利用这两个直角
27、三角形来说明锐角三角形的内角和呢？请同学们以小组为单位研究一下。哪个小组派代表上来说说你们是怎么研究的？是不是所有锐角三角形都能分成两个直角三角形？由此就得到什么结论？（所有锐角三角形的内角和都是180 度。）文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y
28、6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V
29、5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y
30、6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V
31、5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y
32、6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V
33、5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2学习好资料欢迎下载用刚才的方法研究钝角三角形的内角和。小结：通过咱们刚才量一量，折一折，撕一撕等方法的验证可以得出一个什么样的共同结论,（全班小结：三
34、角形的内角和是180 度)师板书：三角形的内角和是180.师：现在你对这个结论还有丝毫的质疑吗？好就让我们用自信的骄傲的语调读出我们的验证结论。三、巩固应用内化提高同学们你们能用这个新知识来解决问题吗？那现在我们一同来闯关吧！1、根据已知角的度数求出未知角的度数（着重让学生说说自己的想法：从而总结出内角和减去已知角的度数就等于未知角的度数）2、求等边三角形的内角的度数3、已知直角三角形的一个锐角是40 度求另一个锐角的度数（提示两种方法，90度减去 40 度等于 50 度）4、放风筝：同学们又是一年三月三风筝飞满天，想去放风筝吗？在放风筝之前老师需要同学们进行一次挑战敢吗？一个等腰三角形的风筝
35、一个底角是70 度，求顶角的度数？5、挑战极限：同学们的挑战精神老师分佩服，老师也进行了一次挑战可是失败了，你能帮助老师吗？文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7
36、Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 H
37、G5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7
38、Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 H
39、G5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7
40、Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 H
41、G5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2学习好资料欢迎下载根据三角形的内角和是180 度的知识求出四、五边形的内角和是多少？四、回顾整理反思提升同学们通过这节的学习你有哪些收获？文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y
42、1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3
43、ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y
44、1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3
45、ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y
46、1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3
47、ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2文档编码:CF5Y1O1D7V5 HG5M8Z3J3X3 ZL2A8Y6R7Z2