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1、平行四边形性质平行四边形性质1Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.活动:按课本98页要求完成一个剪纸活动剪两个全等的三角形,并将它们相等的一组边重合。(1)你拼出了怎样的四边形?(2)
2、可以得到平行四边形吗?你有几种方案?Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.如果你剪的三角形是:(1)直角三角形(2)锐角三角形(3)钝角三角形(4)以上三类中特殊的三角形等腰三角形?Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.长方
3、形平行四边形注:还能拼出三角形。返回Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.平行四边形一般的四边形(有三种)返回Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.平行四边形一般的四边形(三种)返回Evaluation only.Creat
4、ed with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.正方形平行四边形注:还能拼出三角形。等腰直角三角形Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.注:还能拼出一般的四边形。平行四边形等腰锐角三角形Evaluation only.Created with Aspose.Slides fo
5、r.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.平行四边形注:还能拼出一般的四边形。等腰钝角三角形Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.平行四边形注:还能拼出一般的四边形。返回等边三角形Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile
6、 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.大家知道什么样的四边形叫平行四形吗?Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.平行四边形平行四边形(1)定义及表示方法:(2)课堂演示:(3)平行四边形的性质:(4)学有所用:(5)知识出击:(6)超级演练:(8)本课总结:这节课你学到了什么?(7)能力冲浪:Evaluation only.Created with Aspos
7、e.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.记作:ABCD 读作:平行四边形ABCDABCD返回平行四边形中 ,相对的边 ,称为 对边对边 相对的角 ,称为 对角对角其中线段BD就是 ABCD的一条对角线。返回总结 定义:两组对边分别平行的四边形叫做 平平行四边形行四边形Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pt
8、y Ltd.21ABCDADBC ABDC 2用符号表示是:用符号表示是:四边形四边形ABCD是平行四边形是平行四边形Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.课堂演示:将复制后的四边形绕一个顶点旋转180,你能平移该纸片,使它与原来的四边形ABCD重合吗?对边之间、对角之间分别有什么关系?由此你能得到什么结论?返回Evaluation only.Created with Aspose.Slides for.NE
9、T 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.平形四边形的性质:平行四边形的对边相等平行四边形的对角相等返回Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.21ABCD AB=DC ,AD=BC.A=C,B=D2用符号表示是:用符号表示是:四边形四边形ABCD是平行四边形是平行四边形Evaluation only.Created with
10、 Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.ABCD5632cm30cm学有所用:返回得出结论:平行四边形邻角互补。30cm30cm32cm32cm1241245656124124已知已知 ABCD中中,AD=32cm,CD=30cm,A=56,求:求:BC=AB=B=C=D=能能确确定定其其他他三三个个内内角角的的度度数数吗吗?为为什什么么?若若已已知知平平行行四四边边形形的的一一个个内内角角的的度度数数Evaluation only.Created with Asp
11、ose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.B132CABD48 BC=3 cmC48AD返回3 cm平行四边形平行四边形ABCD中中,BC=3cm,A=48求:求:Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.1.ABCD中,中,B=60,则,则A=_2.C=_,D=_.2.ABCD中中A比比B大大
12、20,则,则C=_.3.ABCD中,中,AB=3cm,BC=5cm,则,则AD=_,CD=_.4.如果如果 ABCD的周长为的周长为40cm,ABC的周长为的周长为25cm,则对角线,则对角线AC的长是(的长是().(A)5cm(B)15cm (C)6cm (D)16cm超级演练超级演练120120601005cm3cmAEvaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.5、在、在 ABCD 中,中,ADC=125 CA
13、D=21,求,求ABC,CAB的的度数度数返回超级演练超级演练Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.ABDCE9cm5cm ABCD中,若BE平分ABC,则ED4cm1235cm5cm4cm返回能力冲浪能力冲浪 Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 As
14、pose Pty Ltd.总结ABCD 角角 边边对边平行且相等对角相等邻角互补返回进入知识点(一):定义及表示方法知识点(一):定义及表示方法知识点(二):性质知识点(二):性质Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.Copyright 2004-2011 Aspose Pty Ltd.结束语结束语谢谢大家聆听!谢谢大家聆听!33