1 . [问题初探]
在数学活动课上,李老师给出如下问题;如图1,在
中,
,
,垂足为B,且
求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f12d11c9caa2d667a93a71ea31742161.png)
①如图2小鹏同学从结论的角度出发给出如下解题思路;在
上截取
连接
,将线段
与
,
之间的数量关系转化为
与
之间的数量关系。
②如图3,小亮同学从
这个条件出发给另一种解题思路:作
的垂直平分线,分别与
,
交于F,E两点,连接
,将
转化为
与
之间的数量关系, 请你选择一名同学的解题思路,写出证明过程
[类比分析]
李老师发现之前两名同学都运用了转化思想,将证明三条线段的关系转化为证明两条线段的关系;为了帮助学生更好地感悟转化思想,李老师将图1进行变换并提出了下面问题,请你解答.
如图4,在
中,
,过点A作
(点D与点C在
同侧),若
,求证;
.
在数学活动课上,李老师给出如下问题;如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca15680465a77c5ce6543766f583ceaa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a77e3c1c236141d6118429fade0a9b9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e146bbc92ff020681460bd252b6d33c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f12d11c9caa2d667a93a71ea31742161.png)
①如图2小鹏同学从结论的角度出发给出如下解题思路;在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38ac49caae8e3b8869d19beeff98966e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.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/4eedae8d316c76e3d0b451256de03fb9.png)
②如图3,小亮同学从
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca15680465a77c5ce6543766f583ceaa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca15680465a77c5ce6543766f583ceaa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c543c3ddc3723fde6bbfca3ea3b921b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9940b7a52cfb34f91389c8adac6b69e.png)
[类比分析]
李老师发现之前两名同学都运用了转化思想,将证明三条线段的关系转化为证明两条线段的关系;为了帮助学生更好地感悟转化思想,李老师将图1进行变换并提出了下面问题,请你解答.
如图4,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dceb5cc71fc50f20649f6b9535fd914.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb7a1d7dead053c838decaf271354b6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f12d11c9caa2d667a93a71ea31742161.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/29/ac1a0a75-6998-4c9d-985a-c45e557bb8cb.png?resizew=582)
您最近一年使用:0次
2 . 请回忆华师版八年级上册数学教材第94页的部分内容,该内容阐述了垂直平分线的性质定理:线段垂直平分线上的点到线段两端钓距离相等;并给出了证明的方法.
定理证明:根据教材的分析,结合图①,写出“线段垂直平分线的性质定理”完整的证明过程.
定理应用:
(1)如图②,在
中,直线m、n分别是边
的垂直平分线,直线m、n交于点O,过点O作
于点H.求证:
.
(2)如图③,在
中,
,边
的垂直平分线交
于点D,边
的垂直平分线交
于点E.若
,求
的值是多少?
定理证明:根据教材的分析,结合图①,写出“线段垂直平分线的性质定理”完整的证明过程.
定理应用:
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/28/b52c5e3c-0d4c-44bc-a667-27701a28591d.png?resizew=339)
(1)如图②,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1005d9def461d00556e3aced70ea2f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efeccd375f7ee16b46cc1f5c22d1995f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d03a6074fa932d98728d6d61670aea7.png)
(2)如图③,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3570a95f68349fcd9417fcda62e78e7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dd9cd18275360b87b193b07d8ac8f1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
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3 . 如图,在
中,
,
、
、
分别是
、
、
的中点,连结
、
,求证:
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/18/724ddade-0636-4d5d-8699-1d35b6a6587c.png?resizew=244)
请你结合上述讨论,选择恰当的方法完成证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ab41054fa9ce51b68e78d9c0cf398d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.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/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a6c6e7c025362c46a64a8956761f08e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a679040c4d556723e482bacbab41356d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8f718e34f5af556bd4a0994ad5a80ca.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/18/724ddade-0636-4d5d-8699-1d35b6a6587c.png?resizew=244)
针对这道题,三位同学进行了如下讨论-- 小胡:“需要利用全等证明.” 小吴:“要证中线相等,我想到了直角三角形.” 小明:“我觉得你们都对,但还有别的方法.” |
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4 . 如图,在平行四边形
中,连接
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/17/fe7aeadc-67ac-4c8c-b0eb-bd8489bae6f9.png?resizew=152)
(1)请用尺规完成基本作图:作
的垂直平分线
,交
于点O,交
于点M,交
于点N(保留作图痕迹,并标上字母,不写作法);
(2)已知:四边形
是平行四边形,
垂直平分线
,交
于点O,交
于点M,交
于点N.求证:
.请补全下面的证明过程.
证明:∵四边形
是平行四边形,
∴
,
,
∴
① .
∵
是
的垂直平分线,
∴ ② .
在
和
中,
.
∴
,
∴
④ ,
∴
,
∴
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/17/fe7aeadc-67ac-4c8c-b0eb-bd8489bae6f9.png?resizew=152)
(1)请用尺规完成基本作图:作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(2)已知:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/049ba02a6816033ade98e679a59a3b24.png)
证明:∵四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c220eadc312101e2fb89dfe920f7b30d.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b2d4ab9a735698958f51b3b0bdb82f9.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
∴ ② .
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bebeded5e0e2c715d59cbf80dd067d98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e16ff6c94d9fa9080fe9fad9e8108b56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b49eb5ef41adc49d95845f5bba56650b.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36bbd0c254f0264853c7087b189877a5.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7277d4fa62666459e91b0f16f3756c65.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78a6e5a7e7ec102d6c1b9d106e177737.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/049ba02a6816033ade98e679a59a3b24.png)
您最近一年使用:0次
名校
5 . 如图1,点A、D在在y轴正半轴上,点B、C分别在x轴上,
平分
与y轴交于D点,
,
,
,
.
;
(2)如图2,点E为
上一点,且
,证明:
;
(3)过D作
于F点,点H为
上一动点,点G为
上一动点,(如图3),当H在
上移动,点G在
上移动时,始终满足
,试判断
、
、
这三者之间的数量关系,写出你的结论并加以证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3ad4c0ba3a6750537789844d0ec419d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee33736169c249a029f478a605dc2c05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fec0bc3a43265b63b6964476ca327fab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8df32c7b23e4ca6360cb78745b50f61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75138ba36c21f2216ec99114c9fbbfd2.png)
(2)如图2,点E为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/319925338ac93969871d61aa9a539379.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2b34233772c4c26d6669499d9b1f15a.png)
(3)过D作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/761a77e11e1e45c2a8b2d34d22cf8e04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/828628c0876b45381c9a0edeb0fec236.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/828628c0876b45381c9a0edeb0fec236.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3923dc424cd85ac25f3d757cfbedb2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c83f1f880e5ffbff036953acaca90c41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/307bd991211ec79b47a4be52933bb8e7.png)
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6 . 如图,在
中,
,
于
点,在
中,
,
于
点.
和
的延长线交于点
,连接
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/12/6c97b2dd-b3d4-40a9-a858-c94fc161d741.png?resizew=204)
(1)求证:
;
(2)若
,试判断
的形状,并给出证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ab41054fa9ce51b68e78d9c0cf398d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20b5536e2d24bffb076daf7f5ffe8eb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d01f6f70b5cb3fd3b580e9f298588d6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f3d2da8339463d2154ba982af948534.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91303b2b7d81e5f7f4d167d2be520da1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79ff575e55857af133edb24c8e61504f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935ad59079c158ea0f92018fc548e4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13af018556f0b484ed38519f2edc791c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af6cd332590b9eb4032b51a39134d219.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/12/6c97b2dd-b3d4-40a9-a858-c94fc161d741.png?resizew=204)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03046667fedf78c4b29e1ca9825fac84.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/693407f51dbfc9fec502b75555a6323a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b5c3280f0f89abfaf6a96b7650bd5bd.png)
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名校
7 . 如图,在
中,
,
.
于点
.以
为边作等边
,直线
交直线
于点
.连接
交
于
.
(1)求证:
:
(2)探索
,
,
之间的数量关系,并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6456245b58e20ebc06e8eba9bbff4b13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcb49df05f2e31d005735c3f14a21d30.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/24/93f1d2aa-3c7a-43a4-8bf4-64a763d04849.png?resizew=190)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a36f5dfc85b947863ecb4bb6e246825.png)
(2)探索
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7c57b07f75e97d9f84718bd495ebcf4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12a477603f3f88c3b48352b6130f9ad5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
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8 . 如图,在等边三角形
中,点
在边
上,点
在边
的延长线上,以
为一边作等边三角形
,连接
.
![](https://img.xkw.com/dksih/QBM/2024/1/25/3418913475010560/3422195959939072/STEM/22a280271a0740ceae46700d853cc3a1.png?resizew=237)
(1)若
,求证:
;
(2)试探究:线段
、
、
三者之间的数量关系,并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.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/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/134ef0b1a2669a09f05bd4dc2496f706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://img.xkw.com/dksih/QBM/2024/1/25/3418913475010560/3422195959939072/STEM/22a280271a0740ceae46700d853cc3a1.png?resizew=237)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5eaffcd2070bfcb1955e2cab66c26c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0916a72324358517874dc3c22bc1a7bd.png)
(2)试探究:线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
您最近一年使用:0次
9 . 如图,在四边形
中,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/19/2eaffe39-c327-4b67-9127-26f589cafc1b.png?resizew=161)
(1)在图中,用尺规作线段
的垂直平分线
,分别交
,
于点E,F;(保留作图痕迹,不写作法)
(2)在(1)条件下,连接
,且
,求证:
是等边三角形.请补充图形,并完成下列证明过程.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
垂直平分
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
,
①______,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
和
中,
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
(③______),
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
,
④______,
⑤______,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
是等边三角形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e735a28578ba191da6d4f3b0f8e8729.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/19/2eaffe39-c327-4b67-9127-26f589cafc1b.png?resizew=161)
(1)在图中,用尺规作线段
![](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/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
(2)在(1)条件下,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/004104bafb5f30338123d4ea2b7fedde.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.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/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/076a5273440d800b96bfcaaa9970cc45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7654b4dbc0f9ba23055f4cb65560a223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e81ee3a1a773ca1d7c1b81e452d69000.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/637ed31a01c0abee712b410e81390dd4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/722f767238340c5aa50234dd8fb4de09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2ddd49625097d0a78df7170be4f882e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](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/004104bafb5f30338123d4ea2b7fedde.png)
您最近一年使用:0次
10 . 学习了等腰三角形后,小明发现等腰三角形顶角顶点处的外角正好是其底角的两倍,于是他对作一个角等于已知角的两倍有了新的思路,请根据他的思路完成以下作图与推理证明填空,注明其中蕴含的数学依据:
用直尺和圆规,作线段
的垂直平分线
分别交
于点M,交
于点N,连接
.(只保留作图痕迹)
求证:
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/23/bf29c89a-5fab-4fa7-a082-646dca5b74f2.png?resizew=155)
证明:∵
是
的垂直平分线
∴
① ,(依据: ② );
∴
③ ,(依据:等边对等角).
∵
是
的外角
∴
(依据: ④ );
∴
.
用直尺和圆规,作线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abd13974aebe38eb2a1d744a01ea5aa5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/438f34bc8b04e8c494b91306ac6fe352.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c55ef3bdc97849bb74ccbb6e8e7df3d2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/23/bf29c89a-5fab-4fa7-a082-646dca5b74f2.png?resizew=155)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abd13974aebe38eb2a1d744a01ea5aa5.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b7dc2816d332f8761bfe2db1d9db87e.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a2979f64c85f82d8975d73ee1c342de.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b6500fbe1ea4a372d703502699b809e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c0da03ec477a5e17b7f4de370638024.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4b8dee1c3dde99a6f6334cc728f5bed.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c55ef3bdc97849bb74ccbb6e8e7df3d2.png)
您最近一年使用:0次