圆的初步认识①（课件）-四年级上册数学沪教版

圆的初步认识① 圆的初步认识 在操场的中间画一个很大的圆，你有什么好办法吗？ 固定的点 旋转一周 固定的长度 定点 定长 两种画圆的方法，有什么相同之处？ 圆心（O） O 半径（r） r 旋转一周 定点 定长 在一个圆里，有无数条半径. 在一个圆中，有无数条相等的半径. O r 练习册 P77 A级 4（3） 填空 （3）在同一个圆里，有（ ）个圆心，（ ） 条半径，所有半径的长度（ ）. 1 无数 相等 练习册 P78 A级 6（2） 选择 （2）从圆心到（ ）任意一点的线段，叫半径. A.圆内 B.圆外 C.圆上 C √ 回顾小结 用圆规、绳桩画圆的方法. 在一个圆里，有一个圆心，和无数条相等的半径.圆心用O来表示，半径用r来表示. 圆，一中同长. 胖1 com.apple.VoiceMemos (iOS 13.6) 丁1 com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) 胖2 com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) null 20140.4 com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) null 29910.42 com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) 小亚（而且都） com.apple.VoiceMemos (iOS 13.6) 巧5 com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) 胖5 com.apple.VoiceMemos (iOS 13.6) 丁6 com.apple.VoiceMemos (iOS 13.6) 亚6 com.apple.VoiceMemos (iOS 13.6) 巧6 com.apple.VoiceMemos (iOS 13.6) 亚7 com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) 胖6 com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceMemos (iOS 13.6) com.apple.VoiceM