九年义务教育五年制小学数学第十册.ppt

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1、九年义务教育五年制小学数学第十册圆的认识Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.正方形长方形三角形平行四边形梯形圆Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAs

2、pose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.·O圆心半径r直径d·Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright200

3、4-2011AsposePtyLtd.oCDGHMNBFE图中哪些是半径？哪些是直径？哪些不是，为什么？Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.学习要求：1.请同学们在圆纸片上画出半径，看能画出多少条？2.请同学们用直尺量一量画出的半径有多少厘米？你发现了什么？3.请分四人小组讨论：在同一个圆里，半径有什么特征？直径有什么特征？它们之间有什么关系？Evaluationo

4、nly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.o•同圆内，半径有无数条，长度都相等。Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.o•同圆内，半径有无数条，长度都相等。Evaluationonly.CreatedwithAspose.Slide

5、sfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.o•同圆内，直径有无数条，长度都相等。Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.o•drrEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright

6、2004-2011AsposePtyLtd.o•drrrEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.o•drrrEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.o•drrd=r+rd=2rr=d2Evaluationonl

7、y.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.·O·O’等圆的半径相等，直径相等Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.练习：1判断：（1）在同一个圆内可以画100条直径。（2）所有的圆的直径都相等。（3）等圆的半径都相等。（4）两端都在圆上

8、的线段叫做直径。2口答：r(米)d(米)0.240.861.421.042.6()()()()√×××0.480.432.840.525.2Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfil