利用尺规做图利用尺规可以平分任意一个角,从而可以把一个角四等分,八等分.那麼 如何用尺规三等分任意一个角?

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• 利用尺规做图利用尺规可以平分任意一个角,从而可以把一个角四等分,八等分.那麼 如何用尺规三等分任意一个角?
• 关于“尺规作图三等分一个角”首先,我们很容易做出一个三角形的全等三角形（边边边相等）,于是可以做出任意角的等角；其次,能做出任意角的等角,就能做出一条直线的平行线（同位角相等）；再次,根据“平行线等分线段定理”,在任意线段一端点的射线上连续截取三段等长线段,做两条平行线,就可以三等分原有线段；最后,对与任意角,只须够造等腰三角形,使其为顶角,三等分底边,就可以三等分顶角.为什么那么多人说“尺规作图三等分一个角”不可能?我哪里出错了?等腰三角形里,三等分底边,就可以三等分顶角
• 尺规作图,3等分角尺规作图画3等份任意角成立证明过程如下1,画一任意大小的圆O2,经过圆心做半径,得到线段OA3,以A为圆心,任意长度为半径,画出一点B,不改变现在圆规的半径,再以B为圆心画出一点C,再以C为圆心画D.连接AB,BC ,CD,OB,OC,OD.则有3个全等的等腰三角型.则角OAB=角OBC=角OCD然后进正题:3等分已有角a,因为知道角度大小那么就能得出弧长a和弦DC关键在于如何3等分弧长,用一把足够长的没刻度的咫尺,在尺上刻出弦长,然后3分,得出每段长度为X.(如果连线段都不会3分,你可以回去读初中)然后再以D为圆心,分别以X,2X,3X画圆,与弧长a相交于3点,A,B,C.得出3段相等的弧.然后以匀速圆周运动测量弦DC画圆时,从一个圆与弧的交点,到下一个圆与弧的交点圆,即a交点从D到A,A到B,B到C.C到D的时间是否相等.(解到这里由于物理学知识缺乏,无法继续,找高手求救)
• GMAT Each of the integers from 0 to 9,inclusive,is written on a separate slip of blank paper and the ten slips are dropped into a hat.If the slips are then drawn one at a time without replacement,how many must be drawn to ensure that the numbers on teo of the slips drawn will have a sum of 10?a) 3b)4c) 5d)6e)7 求中文翻译
• 英语翻译Long ago,a King went out to meet his people during a festival.Many poor people stood along the road.They hoped to get present form him.They anxiously waited for the King.After some time,the King arrived on an elephant.Everybody in the crowd pushed to see their King.A begger also came forward with his bowl.There was lots of rice in it."My bowl,my bowl!Give me something to eat,"cried the beggar.The King looked at him with compassion.Then he said,"Gi