数学人教版九年级上册24.1.1圆.ppt

24.1.1圆,LOGO,slidetounlock,2017,马春辉,佳木斯市十九中学,LOGO,如图，在一个平面内，线段OA绕它固定的一个端点O旋转一周，另一个端点A所形成的图形叫做圆,O：圆心；线段OA：半径；表示方法：O；,r,A,O,LOGO,圆可以看成是所有到定点的距离等于定长的点的集合,LOGO,1A、B是O上两点AOB=60，O的半径r=4,求AB,LOGO,2、在O中，AB=CD,求证:AOC=BOD.,LOGO,为什么车轮是圆形的？,Position,车轮为什么是圆形的，而不是正方形或其他图形呢？,圆形,三角形,椭圆形,正方形,三位同学的投圈结果,点在圆外,点在圆上,点在圆内,dr,1.O的r3，若OP4，则点P在；若OP3，则点P在；若OP2，则点P在,2.已知O的半径为6，点M到圆心O的距离OM=4，则点M与O的位置关系为（）A、点M在圆上B、点M在圆外C、点M在圆内D、无法确定,3.已知O的半径为5，点P在圆内，则线段OP的长度可能是（）A、4B、5C、6D、7,外,上,内,C,A,忽然刮来一阵风，将奖品吹得偏离了圆心的位置，但仍在圆内，这时C同学发现A、B两位同学恰是圆上离奖品最远和最近的两点，你知道A、B在哪吗？说说理由。,问题1,方法：作直线OP,O2,r2,O1,r1,O3,r3,O4,r4,O5,r5,O2,O1,O3,O4,O5,A、B、C三位同学很固执，不按设计好的圆形站位，没办法只能移动奖品的位置，那奖品放哪离三位同学的距离是相等的，请找出它的位置并说明理由。,r,LOGO,问题1：点P到O上各点的最大距离为5,最小距离为1,求O的半径.,LOGO,问题2：有一个破碎的圆形镜片，你能将它还原吗？,问题1：点P到O上各点的最大距离为5,最小距离为1,求O的半径.,THANKYOU,LOGO,3、在O中,圆心O是坐标原点,半径为,点P的坐标为(3,4),判断点P与O的位置关系.,O,H,LOGO,3、在O中,圆心O是坐标原点,半径为,点P的坐标为(3,4),判断点P与O的位置关系.,O,H,LOGO,Profits,一切平面图形中最美的圆,一切立体图形中最美的球,历届弟子中最美的是你们,LOGO,圆,1,2,3,4,LOGO,OurCompany,CompanyName,AddYourTextHereAddYourTextHereAddYourTextHereAddYourTextHereAddYourTextHere,AddYourTitle,LOGO,OurCompany,CompanyName,AddYourTextHereAddYourTextHereAddYourTextHereAddYourTextHereAddYourTextHere,AddYourTitle,LOGO,OurTeam,AddYourTextHereAddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHereAddYourTextHere,LOGO,OurAchievements,Products,Deals,LOGO,OurProducts,Computer,CD,Earphone,Game,AddYourTextHereAddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHereAddYourTextHere,LOGO,MarketingMode,AddTextHereAddTextHere,AddTextHereAddTextHere,AddTextHereAddTextHere,LOGO,Deals,SalesModel,LOGO,Store,Online,APP,ServiceObject,LOGO,Company,NOW,School,AddYourTextHereAddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHereAddYourTextHere,Future,LOGO,Whitecollar,Thepublic,AddYourTextHereAddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHereAddYourTextHere,Finance,Cost,Profits,LOGO,Cost,Title,Title,Title,AddTextHere,AddTextHere,AddTextHere,LOGO,LOGO,Cost,LOGO,Profits,AddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHere,AddYourTextHereAddYourTextHere,圆的概念,2ABC,5JKL,0,Cancel,Emergency,认识圆,LOGO,圆的概念,1,2,3,4