1 . 如图,在四边形
中,
,
.
上截取
,连接
,作
的角平分线
,分别交
于点F、G,连接
.(保留作图痕迹,不写作法)
(2)在(1)所作图形中,求证:
.(请补全下面的证明过程,不写证明理由)
证明:∵
是
的角平分线,
∴ ,
∵
,
∴ ,
∴
,
∴ ,
又∵
,
∴ ,
∴四边形
是平行四边形,
∴
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dceb5cc71fc50f20649f6b9535fd914.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a626eb07074f222d52c129b275e173d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be5fc6ead6416492c231c320a5486f86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2947ca8e0cdbeb4aab80ce9e7b63ba98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ab6fb62038b9207669ce6f8309fb142.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
(2)在(1)所作图形中,求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d440215e4ca391884e61b1017e329e4.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2947ca8e0cdbeb4aab80ce9e7b63ba98.png)
∴ ,
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dceb5cc71fc50f20649f6b9535fd914.png)
∴ ,
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a2a40e29b48b7a23bc25eb615bbe5f5d.png)
∴ ,
又∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be5fc6ead6416492c231c320a5486f86.png)
∴ ,
∴四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7419886f571571b57b61a6a8980305e8.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d440215e4ca391884e61b1017e329e4.png)
您最近一年使用:0次
2 . 如图,四边形
是矩形,连接
交于点
平分
交
于点
.
的角平分线交
于点
,连接
;(保留作图痕迹,不写作法与结论)
(2)求证:四边形
是平行四边形.
证明:∵四边形
是矩形,
∴
,
∴ ① ,
∵
平分
平分
,
∴
,
∴ ② .
∵在
和
中,
,
∴
,
∴ ④ ,
又∵
,
∴四边形
是平行四边形( ⑤ ).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d0b0b7d07ac1aebab6b6f1e8c6acdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a635d7620abb851e2131c63668396e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a457b899731577bfe61dda594ae4eec4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdb8eca20ce2c918ea4034ea15210c7f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/269285cf47de45209780078b523ebf46.png)
(2)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
证明:∵四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ff045361a1774085165769608ec4401.png)
∴ ① ,
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fa6f95394a0d93e62ed95035253799d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d3f9b99890e5650853f830170dccea6.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f12a744bfd62512d7b186a5fc09a088.png)
∴ ② .
∵在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea46133f0ce8a230e503f150955c6d6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/684f55970df210065eaa81b898bfdb9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c74792ff1e3ffcacc916a7f1f0228647.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce68b67af24054b057157759cf5417c1.png)
∴ ④ ,
又∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0944865f14b13a772526c4cae4f29c99.png)
∴四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
您最近一年使用:0次
3 . 请把下列证明过程及理由补充完整(填在横线上)
已知:如图,
,
.
求证:
.
(已知),
且
,( ① )
∴
.(等量代换)
∴
.( ② )
∴ ③
.(两直线平行,同位角相等)
∵
,(已知)
∴
.(等量代换)
∴
.( ④ )
∴
.( ⑤ )
已知:如图,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e53497af8899cb299d762f1a4f46a55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4354365ca0929f8a606ed0bf341e4ca.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1839e1828b5d6f596b2b023504479208.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e53497af8899cb299d762f1a4f46a55.png)
且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb2551d99e91a12eb8d45c976f714e8f.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7e5d879e539ef2bbee6156f70503160.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eee9e9b89278a44b24a1580d8b2ae1fe.png)
∴ ③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dc89b88c177060485151747563903d4.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4354365ca0929f8a606ed0bf341e4ca.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c461ce49f5064605d2e7c59d66dc8bcd.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a11029ca6b4b9e7f777af0280cf163c.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1839e1828b5d6f596b2b023504479208.png)
您最近一年使用:0次
名校
4 . 如图,已知
,射线
交
于点
,交
于点
.
(在
的上方)作![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18bf01503c35ab5e999fad761572ee85.png)
(2)求证:
.
证明:
(已知),且
,
(________),
,(________)
________![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53e519cdb0cac3981d8e9610dba507a3.png)
又
(已知),
(________)
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a11029ca6b4b9e7f777af0280cf163c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/826c728050e3378921442ace20269ef6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/826c728050e3378921442ace20269ef6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18bf01503c35ab5e999fad761572ee85.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7338856efe43dac491864dc1e9bdde90.png)
证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da4600b023d0da1f2f697aa897043d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ea680735565bfa76db27d7c6c970197.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec5ba4cba99b9b1912068bb501ef00e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14d0d07ef7dc7d04b02e25e7fe6c0e3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39681f4995dc582a47459607cc6bbb64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53e519cdb0cac3981d8e9610dba507a3.png)
又
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60cc741b6fba7ce725bf7bb6270c8ba2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bda281982119ab3bdc8abfc05ad2f5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b671ec535aca897737896faf797a670.png)
您最近一年使用:0次
5 . 小明在探究“夹在一组平行线间的线段的垂直平分线与平行线相交后所构成的四边形的形状”时做了如下操作,请你完成小明的操作:如图,在四边形
中,
,
是对角线.
的垂直平分线
,
分别交
,
,
于点
,
,
,连接
,
.(只保留作图痕迹)
(2)在(1)问所作的图形中,求证:四边形
为菱形.(请完成下面的填空)
证明:
垂直平分
,
①______,
,
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f18891e50f85c33319d256f48d224da.png)
在
和
中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbd903f72cc979e0c254c4e96b87a108.png)
,
③______,
,
四边形
为平行四边形,
又
④______,
四边形
为菱形.
请你依照题意完成下面命题:夹在一组平行线间的线段的垂直平分线与平行线相交后⑤______.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dceb5cc71fc50f20649f6b9535fd914.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
(2)在(1)问所作的图形中,求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c87e1fe20bb0e8292e993657e14bc79a.png)
证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/173f7d26d069c0f16a0f6fcb517aa28c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c672f693a7e75a7bae4936dcb1920430.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb6706c88443ead35c76bcf2f3ec24aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f18891e50f85c33319d256f48d224da.png)
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf81da91f4f486850d143c5963abc13f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ac0b5d17fa816eaccc1bac76e03180e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbd903f72cc979e0c254c4e96b87a108.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15b50e381498a61e24b6e7cb2dc33b62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abef313fcb5f27ddaa76ec395dea7a2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c87e1fe20bb0e8292e993657e14bc79a.png)
又
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c87e1fe20bb0e8292e993657e14bc79a.png)
请你依照题意完成下面命题:夹在一组平行线间的线段的垂直平分线与平行线相交后⑤______.
您最近一年使用:0次
名校
6 . 学习了平行四边形的知识后,同学们进行了拓展性研究.他们发现作平行四边形一组对角的角平分线与另一组对角的顶点所连对角线相交,则这两个交点与这条对角线两侧的对角顶点的连线所围成的封闭图形是一个特殊四边形.他的解决思路是通过证明对应线段平行且相等得出结论.请根据她的思路完成以下作图和填空 :
用直尺和圆规,过点
作
的角平分线,交
于点
,连接
、
.(只保留作图痕迹)
已知:如图,四边形
是平行四边形,
是对角线,
平分
,交
于点
.
求证:四边形
是平行四边形.
是平行四边形,
∴
,① ,
∴
.
∵
平分
,
平分
,
∴
,
.
∵![](https://staticzujuan.xkw.com/quesimg/Upload/formula/681e986b62f60ee4d5253aeec4919393.png)
∴② ,
∴
.
∴
,
.
∴③ ,
∴四边形
是平行四边形.
同学们再进一步研究发现,过平行四边形任意一组对角的顶点作平行线与另一组对角顶点所连对角线相交,均具有此特征.请你依照题意完成下面命题:
过平行四边形一组对角的顶点作平行线与另一组对角顶点所连对角线相交,则④ .
用直尺和圆规,过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
已知:如图,四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3981e7286d41960daf4e110c1c84e03a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2330c01a4d2b5b20f106e3e48834d5c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b8bee1c892473f71a723860b933e234.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f716c6fc2918a0b2a75c32792100b7b.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3981e7286d41960daf4e110c1c84e03a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c42b59b76eafbbe36f13b2daa60132c.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51cb729ead99bfb4b8c2d28c8211cb40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da16256a12fd6058e2cdb8f5dc00dd74.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/681e986b62f60ee4d5253aeec4919393.png)
∴② ,
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e850784c5a3f2535ea9771c280f2070d.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86d1125b47dec1c5e93143ee59ad862a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a163ce4079c55e223b0ab5aa2807f684.png)
∴③ ,
∴四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2330c01a4d2b5b20f106e3e48834d5c0.png)
同学们再进一步研究发现,过平行四边形任意一组对角的顶点作平行线与另一组对角顶点所连对角线相交,均具有此特征.请你依照题意完成下面命题:
过平行四边形一组对角的顶点作平行线与另一组对角顶点所连对角线相交,则④ .
您最近一年使用:0次
名校
7 . 如图,在平行四边形
中,点E是
的角平分线与
的交点,小谷想在平行四边形
里面再剪出一个以
为边的平行四边形,小谷的思路是:作
的角平分线,将其转化为证明三角形全等,通过一组对边平行且相等的四边形是平行四边形使问题得到解决,请根据小谷的思路完成下面的作图与填空:
的角平分线与
交于点F,连接
,
.(保留作图痕迹,不写作法,不下结论)
(2)根据(1)中作图,求证:四边形
为平行四边形.
证明:∵四边形
为平行四边形,
∴
,①_______________.
∴②_______________.
∵
分别平分
.
∴
,
.
∴③_________________
∵在
与
中,
∵
,
∴
.
∴
,④_________________.
∴
,即
,
∴⑤________________.
∴四边形
为平行四边形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4189a0821a0ffab9dc171ecd279ba442.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/727ad3e630a224303d6d3b8ad5c114ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/727ad3e630a224303d6d3b8ad5c114ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
(2)根据(1)中作图,求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
证明:∵四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a657ebb70cff27ef82d3ed4808bb659.png)
∴②_______________.
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21b1efb5d9072a67be9d5497a783016c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d6afaa833ca3e0d781ea4d9300267d7.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efd4597fbff1a9384a7672361013c786.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2aa5c103de05ef3ff3650191c6cb8565.png)
∴③_________________
∵在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c771a4feb150ad9cff8d70431c97eb17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/473bc8c16695f150a3f387a43eabcc9b.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca897954cfebeb1903ecd8fc64e9439c.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6df7d16a6370324937f835eceada5ff9.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8ce1475f537b4ad21775bfaa16daa0c.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/335d08afb9fddc585cc7f609dca887b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38cb521079f1fa38b7831f882b93df2d.png)
∴⑤________________.
∴四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
您最近一年使用:0次
2024-06-04更新
|
108次组卷
|
2卷引用:重庆市綦江中学2023-2024学年八年级下学期期中数学试题
8 . 如图,
于点
,
于点
,
,求证:
.
(已知),
∴
(垂直的定义),
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3e24c2bdad41127f07c6639a357d2b8.png)
① (
)
∴ ③
(两直线平行,同旁内角互补)
(已知),
(
)
(内错角相等,两直线平行)
(
)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5f215a42c4b7078d8d65923eb9980e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc90fee532e50d319081d571410421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9fe0c3df8751cb6820a7a6dd40d6344.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/037d72d31ec26f00b1b65d572dda828f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a1296c9fb4c67ea47956b8f877366b9.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d41c1bc618b9626d10798d5c95c3c62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3e24c2bdad41127f07c6639a357d2b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/638537c0a30676c73fea76c80e0f8bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c650fe55b7603f106c53ca2423451c6.png)
∴ ③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81946868f5184bc6f4fcf970c0322483.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f2ea02cb4f1c4922216a3b69707df41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/228e0702379b03ac6d204dd716c8f488.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d8b8edd94bc4d5d517ec77e56800e41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32affbf663d7364a79815b4af9aa90d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d879040774a3704e3850249d8286615a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5de7958890f35a4e42c700044a9c4c87.png)
您最近一年使用:0次
名校
9 . 思考:我们知道,菱形的对角线互相垂直,反过来,对角线互相垂直的平行四边形是菱形吗?可以发现并证明菱形的一个判定定理:对角线互相垂直的平行四边形是菱形.
已知: ,求证: .
证明: .
(2)如图2,在平行四边形
中,对角线
和
相交于点O,
,
,
.求证:平行四边形
是菱形.
已知: ,求证: .
证明: .
(2)如图2,在平行四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf7679c8b4b1e442ce4286d4b0e9c32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4494a85de0be0b97a69348115aef8513.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/454328a8e75953fdb0835ce80d9566e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
您最近一年使用:0次
10 . 如图,四边形
是平行四边形,
于E.
于点F,连接
.(要求:保留作图痕迹,不写作法,不下结论)
(2)求证:
.将下面的过程补充完整.
证明:∵
,
,
∴①____________,
;
∵四边形ABCD是平行四边形,
∴②____________,
,
∴③____________.
在
和
中,
,
∴
,
∴④____________,
又∵
,
∴四边形
是⑤____________;(⑥____________)(填推理的依据)
∴
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53c51c25b65a37b676ae3c3b71c29f9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aac18b0388014ae20b2add2975ef56aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a42c17fe4d91d67c1fa43f966bffd891.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53c51c25b65a37b676ae3c3b71c29f9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aac18b0388014ae20b2add2975ef56aa.png)
∴①____________,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/017df1ca516ca4e4bc814b494d2ca49b.png)
∵四边形ABCD是平行四边形,
∴②____________,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
∴③____________.
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d4ce3f962c91f0d3c7b998b5fbb37b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf88afcfaf964ef01a4b62dadadc0c99.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8efa4a7b9e27aa6483150ea714dbe1b.png)
∴④____________,
又∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed619e2dc900c52a29012e5b821451bc.png)
∴四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9766e5eb6796dafc5ffe212afdfc43c0.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a42c17fe4d91d67c1fa43f966bffd891.png)
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