正十九边形
![求正十九边形的尺规作图法!](https://imgs.wantubizhi.com/img/A1A61BAA66193547F3A6DD7D8EE527E9D4F618E7CC5983642C723DE3A232638F627381CBF0D57AA079F0E9A89143C6B7F514CA11FB610562D1712A1CAE05CD30EC227E5366835AA57CABA4151197BB390694118D2DBAF8AE212EA538D2616ECF)
求正十九边形的尺规作图法!
图片尺寸477x485![正十九边形中文维基百科【维基百科中文版网站】](https://imgs.wantubizhi.com/img/ADDA3C5D760C6828B77B505A29D43E83B060EDE3430AE63B0BE4E9972AAA761F0F8753E0C9083CC890894545D00888DE60C8BA213D75F92A9AB548BADA3B73CDCF4B45B838635C29C4FDB1033BE0156937EC85093CBE2CC985DB6F1030C5F04E)
正十九边形中文维基百科【维基百科中文版网站】
图片尺寸220x220![【数学 尺规作图】17 正19边形(近似)](https://imgs.wantubizhi.com/img/ADDA3C5D760C6828B77B505A29D43E834672271218AE0BFAF1A70EAE70FF2062F924DFCDF3807E8A2B92FEE42C8E8C777FAD54312C10D3E1B66E72ECF9C5BD3A45910A7597D71340E1151E9F0889D9B7AFAF078907C9EF1E51833E63CBBB8A08)
【数学 尺规作图】17 正19边形(近似)
图片尺寸1500x940![九边形](https://imgs.wantubizhi.com/img/A1A61BAA66193547F3A6DD7D8EE527E90C995CC4AD58D89754F0A5F8DD34EABDCF9F5DB3EC13592BB8EC4144B06DC165C58EBDA08A4C44D02CEF0617A85C3E4A0055E3A693E15EF9F908AE4D5359E1D2C000875484419C53A9556EE04FF84758)
九边形
图片尺寸259x259![数学奇迹-千古难题"作正19边形"; (有人说"正19边形"如"永动机"不](https://imgs.wantubizhi.com/img/ADDA3C5D760C6828B77B505A29D43E838792129988AE17C605D59B9D8879A830CF72DDCB0C9DA00F7717A668D9D29692C56851E4F57543B7F54CEAA38C822283DA2EA740835D88548A79102506EFA8711CC5E81EBDCCF11FA38A089DA58F348D)
数学奇迹-千古难题"作正19边形"; (有人说"正19边形"如"永动机"不
图片尺寸868x1280![2,多边形命令(pol),绘制内接于圆(i)的正三边形.](https://imgs.wantubizhi.com/img/735A5D1F980B52A636CC46F12F2D1A730C5755F390F73B6D052BAECF4A6E9FA2CB606FADC515F752849647B48C641DEBDCEA87F583AD81F7E0E3D95FD7E5595435996D8D03D8B47BBE6D052AF11C75D47E8FEDC6E2B04E23A66439F9B29FEB13)
2,多边形命令(pol),绘制内接于圆(i)的正三边形.
图片尺寸583x543![大正方形abcd的面积是64平方厘米,其他点都是他们所在边的中点.](https://imgs.wantubizhi.com/img/735A5D1F980B52A636CC46F12F2D1A73BFE0B057A54CAE04F1AF8A9E11759228BB29B016884255579509C98D162B4D29723EC71F2E31EF799F7DCD617A989E1FA2813F55EB073799309B557D8B31999F42F6546800333D1A707E02EC5FFF1BDC)
大正方形abcd的面积是64平方厘米,其他点都是他们所在边的中点.
图片尺寸285x245![求证:bd=ec ed {看图} 向左转 向右转](https://imgs.wantubizhi.com/img/A1A61BAA66193547F3A6DD7D8EE527E9F9826CB07E0210A84B86F4731BF4315B4910955E2C840605EB5D63ECF0453A210099A63752A686BE2552B736A7CAAE15EAD0AC9FAA62BEAC4456F037DBD8EA902A2F5BC2F8AA1BDCBB868DAB32772DCE)
求证:bd=ec ed {看图} 向左转 向右转
图片尺寸890x534![高斯到十九岁时,就从一个数学天才,变成了一个伟大的数学家,他创造了](https://imgs.wantubizhi.com/img/ADDA3C5D760C6828B77B505A29D43E832D584DB2224E52B32980ADA76B36C28FD18C8631B8891C4CF3BC0BED1C6877F09239D94FCD89362A8A6C1939521FBDA7032FF261C187761C5DD9F26B3208D06A612306EE611DE377AB3822EBA0599D64)
高斯到十九岁时,就从一个数学天才,变成了一个伟大的数学家,他创造了
图片尺寸658x429![数学奇迹-千古无解"正19边形"尺规解; 1796年高斯完成二千多年难题"](https://imgs.wantubizhi.com/img/ADDA3C5D760C6828B77B505A29D43E8336E3D839F9C7F45CBAD3DA7A12523C88257CC3FCD5C653D6A1C7BF1C8E23437D75ECB91D6D18ED308FCC4F7D18C969DB25774E8062CD6547F615582DD1A03BF6)
数学奇迹-千古无解"正19边形"尺规解; 1796年高斯完成二千多年难题"
图片尺寸1056x1280![数学奇迹-千古无解"正19边形"尺规解; 1796年高斯完成二千多年难题"](https://imgs.wantubizhi.com/img/735A5D1F980B52A636CC46F12F2D1A736ACC950E3FBB50A1B128CA1D627727FEA31370A50D87288A60CF01D8518085E7D49D22B9EAF5120150496D929560C6DE5257F5A2D484919E58B24A5F7535C07D)
数学奇迹-千古无解"正19边形"尺规解; 1796年高斯完成二千多年难题"
图片尺寸960x1280![ac边上的中线,bd把△abc的周长分为9cm和15cm两部分,求三角形各边](https://imgs.wantubizhi.com/img/735A5D1F980B52A636CC46F12F2D1A73CE44270B62E42FA7C0B7E1C320805733D60B99B3742FAA0BF5724B3A470186702161249EF3D0167728354E03016B5DA29B2FC78E80F96CCD3DCDFBF897B18BDBFE25BD918AA2A99F271E2C93BB7D1B5B)
ac边上的中线,bd把△abc的周长分为9cm和15cm两部分,求三角形各边
图片尺寸450x281![三角形abc中,ab等于ac,角bac为锐角,cd为ab边上的高,i为三角形acd的内](https://imgs.wantubizhi.com/img/ADDA3C5D760C6828B77B505A29D43E837231709A5F5224A90526CAE06737D60265AE07C309D0F676433C0F63570E1911B963E34524B9ADAC87054534F71FEC2589F5B16ECBE2FE760AD21F0E7CAA984B5EF384649743A3ECC0E70B464B676E41)
三角形abc中,ab等于ac,角bac为锐角,cd为ab边上的高,i为三角形acd的内
图片尺寸450x259![绘制出完美的高斯17边形 @geogebra](https://imgs.wantubizhi.com/img/735A5D1F980B52A636CC46F12F2D1A734166AD16E80BADB29E6FDDF8781A077F7E5715DFCE6B6C7D4EA9065D6192BD43360859A5C99144AA88CEDC36A5F0E3F49C6A9DD8BA0EFA2374654A90F2D1ABE4D56BF8442DF03C16D91E29E9E9AFA717)
绘制出完美的高斯17边形 @geogebra
图片尺寸797x498![正十七边形 岁](https://imgs.wantubizhi.com/img/ADDA3C5D760C6828B77B505A29D43E839136C8AEB658BCB81176F40219A8D7B1403E7961DA7C3F5A931C1C260525E3E2DC3C0A98DEE11CCDC57150E62FC4765DA8FB4BACB0F308F9D1722BA5336931350B2F61435703BA540F27A6A6E03189AD)
正十七边形 岁
图片尺寸1080x810![从九边形的顶点中取三点作三角形,并使九边形的中心,即圆心落在三角形](https://imgs.wantubizhi.com/img/735A5D1F980B52A636CC46F12F2D1A733748E8B66B593BED31FB2A286E5C6C673F63B75BC282310F5CB54457E783DC76E3DEB699F4C8E04F461ABF69DF59866D80578C5A8554EA9E254095F22511420EF79C1E652A8B06AB5A284B2F10A1D3D9)
从九边形的顶点中取三点作三角形,并使九边形的中心,即圆心落在三角形
图片尺寸450x450![三角形abc中 ac=bc 角c=20度 点m在ac边上 点n在bc边上 且满足](https://imgs.wantubizhi.com/img/ADDA3C5D760C6828B77B505A29D43E8338A67CD84D72636DC29E50615DC9F5D6D95A74D8FFAA5A7F90A3ADA4E0A514656BCC64DC0CFC579E8223388F6CE2A708BC9E2DDEE51E3353615F7102C8E3F72186967C9845546A5ABBC4B05536590AAB)
三角形abc中 ac=bc 角c=20度 点m在ac边上 点n在bc边上 且满足
图片尺寸500x375![2017年春季学期新版沪教版八年级数学下册19四边形小结与复习学案答案](https://imgs.wantubizhi.com/img/735A5D1F980B52A636CC46F12F2D1A73137A4D4FC75F35FC2F02B8A22025BC40975F972EA419796EADD5A050EB557B28B79BF03DAC4D4B091CE7F2CEB3C011BC6D4B210F507729586DC1EBF60A2C1089A1A2BB5D49C9C6C4DBEB6AFD2902AB7E)
2017年春季学期新版沪教版八年级数学下册19四边形小结与复习学案答案
图片尺寸398x592![中, ,以 , , 为边向外作三个等边三角形,其中心依次为](https://imgs.wantubizhi.com/img/ADDA3C5D760C6828B77B505A29D43E83B52BA76DF32A9AC9CB17166E0ECCF26B8913883BDC4684D883CA3050AD2C34A9A51FD89A3D56799B3BDD913E4DF0A5053E881558C4F63E360A0115AE82D35FD2C010098EC22DBE7E76754C7955935EAB)
中, ,以 , , 为边向外作三个等边三角形,其中心依次为
图片尺寸236x245![如图,△abd三边相等,三角形等,△eac三边相等,三角形等,af⊥cd于f,ah](https://imgs.wantubizhi.com/img/735A5D1F980B52A636CC46F12F2D1A738D0A89D8A30DD5A7561BFCC63259720A6ED4053A59ED8245265B0F86D2691175BDC68052B3C387D80DD3316D54BA994DCDE88F0585B8682E419CC8BD8FA9CA487AD91FADE2851E9A9D1049A5FAB631DC)
如图,△abd三边相等,三角形等,△eac三边相等,三角形等,af⊥cd于f,ah
图片尺寸596x324