如图,在
中,点
、
分别为边
、
的中点.
是平行四边形;
(2)延长
至点
,使
,若四边形
是菱形,则四边形
是什么特殊四边形?证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2330c01a4d2b5b20f106e3e48834d5c0.png)
(2)延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/240100a92f24e93269f1c74ae742b121.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2330c01a4d2b5b20f106e3e48834d5c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf82c9e51bf38d5ff16fc160dd620947.png)
更新时间:2024-05-09 13:36:23
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】已知如图,B是
的中点,
,
.
交
于
点.求证:
![](https://img.xkw.com/dksih/QBM/2022/10/14/3087693030629376/3088060230254592/STEM/52546c16dd9644ea82d83cee7f4fd745.png?resizew=161)
(1)
;
(2)
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99d9d6946f3d30d1c60affa59a081889.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77393d86b856daad357e627e546c6752.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/655b6a742dbacdab5aaa298007663dd4.png)
![](https://img.xkw.com/dksih/QBM/2022/10/14/3087693030629376/3088060230254592/STEM/52546c16dd9644ea82d83cee7f4fd745.png?resizew=161)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f01fb34062af96f8ba7e1e05fb5f862.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b77d74c2fbb2d41e465d04ecdcd55b1.png)
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解答题-问答题
|
适中
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【推荐2】如图,用硬纸板剪一个平行四边形ABCD,找到对角线交点O,用大头针在点O处将一根平放在平行四边形上的细直木条固定,并使细木条可以绕点O转动,拨动细木条,可随意停留在任意位置.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/20/029434a9-215a-4acb-8037-0c01c6b43ea7.png?resizew=461)
(1)木条把平行四边形ABCD分成了两部分,在拨动细木条的过程中,两部分的面积是否始终相等?答: (填“是”或“否”);
(2)木条与▱ABCD的边AD,BC相交于点E,F.
①请判断OE与OF是否始终相等,并说明理由;
②以A,E,C,F为顶点的四边形是平行四边形吗?为什么?
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/20/029434a9-215a-4acb-8037-0c01c6b43ea7.png?resizew=461)
(1)木条把平行四边形ABCD分成了两部分,在拨动细木条的过程中,两部分的面积是否始终相等?答: (填“是”或“否”);
(2)木条与▱ABCD的边AD,BC相交于点E,F.
①请判断OE与OF是否始终相等,并说明理由;
②以A,E,C,F为顶点的四边形是平行四边形吗?为什么?
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解答题-证明题
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适中
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【推荐2】如图,已知:在△ABC中,AB= AC, ∠BAC =30°,D是BC的中点,DE⊥AB于E,DF∥AB交AC于F.
求证:DE =
DF.
求证:DE =
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://img.xkw.com/dksih/QBM/2020/9/18/2552326900375552/2552491863425024/STEM/6e8d9f80a3cc4c45b2219f5b300ab985.png?resizew=200)
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解答题-作图题
|
适中
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名校
【推荐1】如图,在
ABCD中,连接BD,BE平分∠ABD交AD于点E.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/18/7511bf97-efea-4290-97ee-15732300f95f.png?resizew=135)
(1)用尺规完成基本作图:作∠CDB的平分线DF交BD于点F(保留作图痕迹,不写作法);
(2)根据(1)中作图,若AB=DB,求证:四边形DFBE是矩形.
证明:(2)在平行四边形ABCD中
∵
,
∴∠ABD= ① ,
∵BE平分∠ABD,DF平分∠CDB,
∴∠EBD=
∠ABD,∠FDB= ② ,
∴∠EBD=∠FDB,
∴ ③ ,
∵
,
∴四边形EDFB为平行四边形,
∵AB=BD,BE平分∠ABD,
∴ ④ ,即∠DEB=90°,
∴平行四边形DFBE是矩形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81a5328919a7cec382c2e91c9c528fc1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/18/7511bf97-efea-4290-97ee-15732300f95f.png?resizew=135)
(1)用尺规完成基本作图:作∠CDB的平分线DF交BD于点F(保留作图痕迹,不写作法);
(2)根据(1)中作图,若AB=DB,求证:四边形DFBE是矩形.
证明:(2)在平行四边形ABCD中
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a11029ca6b4b9e7f777af0280cf163c.png)
∴∠ABD= ① ,
∵BE平分∠ABD,DF平分∠CDB,
∴∠EBD=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
∴∠EBD=∠FDB,
∴ ③ ,
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3139e28714bfc3d5d875d78dd245d2e.png)
∴四边形EDFB为平行四边形,
∵AB=BD,BE平分∠ABD,
∴ ④ ,即∠DEB=90°,
∴平行四边形DFBE是矩形.
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解答题-证明题
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适中
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【推荐2】如图1,已知四边形
四条边上的中点分别为
、
、
、
、依次连接
、
、
、
、得到四边形
.
为平行四边形;
(2)连接
与
,当
与
满足什么条件时,四边形
是矩形?
(3)如图2,若四边形
是菱形,则四边形
是什么图形,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a16f5621716bfef7a056a3f2712feb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
(2)连接
![](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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
(3)如图2,若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
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解答题-作图题
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【推荐3】【教材呈现】如图是华师版九年级上册数学教材第103-104页的部分内容.
【定理证明】小明根据教材图24-2.2的提示,证明过程为:延长
至点
,使
,连接
、
…,结合图①帮助小明完成直角三角形的性质;“直角三角形斜边上的中线等于斜边的一半”的证明.
【定理应用】如图②,在
中,
,垂足为点
(点
在
上),
是
边的中线,
垂直平分
,则
与
的关系为_________.
【拓展提高】如图③,在
中,
,
,
恰好是中线,则
的度数为_________.
如图24.2.1,画![]() ![]() ![]() ![]() 最一量,看看 ![]() ![]() 相信你与你的同伴一定会发现, ![]() ![]() 下面让我们用演绎推理证明这一猜想. 已知:如图24.2.2,在 ![]() ![]() ![]() 求证: ![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df34369163e511f14028168cb0b21186.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
【定理应用】如图②,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e72b2e1ff83e95df048745322982451.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db866ecc0c098bfc32ec8a43b65bdd58.png)
【拓展提高】如图③,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d3c9ce32b721995f355eea411340e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25ab46164b23af7a4c4907f176e392ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/8/2ac59852-e3b2-447d-b488-914a2b48f824.png?resizew=428)
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解答题-证明题
|
适中
(0.65)
【推荐1】已知:如图,在菱形
中,
,点
、
分别在
、
上运动,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/25/69acdc17-5ba9-44b5-9dcb-ba88c44b0c76.png?resizew=178)
(1)试说明:
.
(2)判断
是什么特殊的三角形,并证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32436704a722d5e568ff5c175bf3c662.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97075fe3c2a105f5d2d0a27a9f2b3410.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/25/69acdc17-5ba9-44b5-9dcb-ba88c44b0c76.png?resizew=178)
(1)试说明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f4327ea35caa3b4aab5da25b7ee8a91.png)
(2)判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35e5a933a2a0ff3a28009cc989293ff5.png)
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解答题-问答题
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【推荐2】如图,在平面直角坐标系中,
为坐标原点,
、
两点的坐标分别为
和
,抛物线
经过点
和点
.
(2)将
沿
轴向左平移得到
,使得四边形
是菱形,试判断点
、点
是否在该抛物线上.
(3)在(2)的条件下,若点
是
所在直线下方抛物线上的一个动点,当
的面积最大时,求点
的坐标,并求出此时的最大面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a02db6c758f1871212d89e22d91a84de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a209bbad0b0f53524d84e69387b0387.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2299f88146e5a525b515a2ed36dfd1fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/102df0e64d65e92d12272fe1713e67df.png)
(2)将
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2b83beedb3438153e6f728545fe3e03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a0acc93490a6a784eb62201d93dd93d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
(3)在(2)的条件下,若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26e59b7c0d4a0b312e674b7bb061240b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
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