1 . 如图,在
中,
,
于点E,BE=AE,
是
的角平分线,和
相交于点P,和
边交于点D,点F是
边的中点,连结
,交
于点Q,连结
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/1/666fea43-eaa6-4b62-8ed7-6c20d2fe942c.png?resizew=126)
(1)求证:
;
(2)求证:
;
(3)判断
的形状,并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d320f180419175d75eebc618cc458b39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb6ede9761b5b90f8dc137708e1ee90f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/1/666fea43-eaa6-4b62-8ed7-6c20d2fe942c.png?resizew=126)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e8cd82dfa1665812741dac164ee964d.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e184ce1eb15152542349abf825c7b3e8.png)
(3)判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab142c659d5434d88d7f6f5d994cfd18.png)
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2 . 如图,在
中,
平分
交
于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/21/4f170d67-72fa-4e13-baf7-54751e36a405.png?resizew=242)
(1)用尺规完成以下基本作图:过点
作
于点
,交
于点
,连接
;(不写作法,不下结论,保留作图痕迹)
(2)求证:
,请根据下列证明思路完成填空:
证明:
____________,
.
于点
,
(____________)
在
和
中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/229ad9e4aa38b247f1abf8f938280852.png)
(____________).
____________
是线段
的垂直平分线
(____________)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.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/8455657dde27aabe6adb7b188e031c11.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/21/4f170d67-72fa-4e13-baf7-54751e36a405.png?resizew=242)
(1)用尺规完成以下基本作图:过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07d6b98ecb4793c9f063f1f6b61caa19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ad98ad714864041a632ca949308e417.png)
证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/113bffa74ac1e976a5c468ccde2dc860.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6f75cd01b3689408ebb2bcea4b25f6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d257e50f224710383ad7a1b2da603d4.png)
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48d671ea595b1a638992a531471ab47c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/022f0dc17db5fcc83b204dc845447ffc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/229ad9e4aa38b247f1abf8f938280852.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b87d978d02e1ccc8112746d456dcbab7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56577eaa2f4ed14e6e4330a801a59293.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a860c6ab2c48b1c458f54fdb23fa8bd.png)
您最近一年使用:0次
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3 . 如图,已知四边形
中,
为
边上一点,连接
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/20/57413150-be9b-4eda-bf84-0ad1e2dfcede.jpg?resizew=170)
(1)用直尺和圆规完成以下基本作图:过点
作
的垂线交
于
(保留作图痕迹);
(2)在(1)的条件下,若
,
,
为
的角平分线.
求证:
.完成下列填空.
证明:∵
,
,
①____________,
,
为
的角平分线,
,
②____________,
,
,
即:③____________,
∴
④____________,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/826c728050e3378921442ace20269ef6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/20/57413150-be9b-4eda-bf84-0ad1e2dfcede.jpg?resizew=170)
(1)用直尺和圆规完成以下基本作图:过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
(2)在(1)的条件下,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e472dea21dbfb4ab929e970d4bcbcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cd9f2ab635fbcde5f49a7919fe0b8a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/826c728050e3378921442ace20269ef6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38968daa1e0f0a5caceb3ede903105ad.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f7de19ceb054d778b94d849337d8a02.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e3f5dc11efe60b4fd9a13b1d6b83842.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e472dea21dbfb4ab929e970d4bcbcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d8cbe6e341b308d8551751e2c6b3c65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/671c73a48dfce4894545ae665b17f77d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84c38ffc474f45993a7ed1e3cd5da75a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/579b7a12dffd2b0be7ad5fa4ec9106e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0eccaabe3cd78d3974282019505fb9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/353ab7837467b911fcc5983af6339793.png)
即:③____________,
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a8a9dedc0ea544bcdc304a6f6016aed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0268b7417bbdd8a53d0659399a6a8317.png)
您最近一年使用:0次
4 . 在
中,
,
是边
的中点,
于点
,
平分
.
(1)求证:
平分
;
(2)过点
作
的垂线交
的延长线于点
,
①求证:
;
②
是什么三角形?证明你的猜想.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ce7f6d278f2ef7a193b7eed7be6b3c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82da6815bc213dfd78c2f77cd7ded8ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e8d0d5254ed9e296b76ac3b4d40a13a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b664f3a011a2f1f31c66a2635c5367c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/20/dbe31eb8-5657-47aa-a8dc-7f778270aa59.png?resizew=170)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b05e9b20f0048c8a296ec86e21d33fb.png)
(2)过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
①求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccdee92eb6770033f7953f5622e0e506.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f086e5309e9d6e3aca2de90667f1a2c5.png)
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5 . 阅读与思考
(1)【特例呈现】
如图1所示,数学活动课上,在折叠等腰三角形纸片的过程中,小明发现:等腰三角形底边中点到两腰的距离相等.请利用图2证明这个命题.
已知:如图2,在等腰
中,
,点
为
中点,
于点
,
于点
.
求证:
.
(2)【一般探索】
在动手操作探究过程中,小明又发现,对于任意的等腰三角形,若将“点
为
中点”改为“点
为三角形外部一点,满足点
到等腰三角形的两顶点
的距离相等”,都能得到点
到两腰所在直线的距离相等,如图3所示.请补全已知,并证明.
已知:在等腰
中,
,
于点
,
于点
, .
求证:
.
(3)【问题拓展】
小明继续探究:利用已有学习经验,尝试改变条件和结论位置,提出猜想:对于平面上的一点
,若满足点
到一个三角形的两顶点
的距离相等,且点
到边
所在直线的距离相等,那么这个三角形是等腰三角形.小明认为这个猜想一定成立,但他的同学小强认为这个猜想不一定成立,你同意谁的想法?若同意小明的想法,请画图并说明理由;若同意小强的想法,请画出反例.
(1)【特例呈现】
如图1所示,数学活动课上,在折叠等腰三角形纸片的过程中,小明发现:等腰三角形底边中点到两腰的距离相等.请利用图2证明这个命题.
已知:如图2,在等腰
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.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/32c38dfd14dde969702dff97ef2270f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/761a77e11e1e45c2a8b2d34d22cf8e04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7faabc484ce3666706c1beffda4bcfe2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/20/26ece633-1bff-4d47-b7c8-09b14f558584.png?resizew=385)
(2)【一般探索】
在动手操作探究过程中,小明又发现,对于任意的等腰三角形,若将“点
![](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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0520e9675bc1b416e8b8f01eb69fd13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
已知:在等腰
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32c38dfd14dde969702dff97ef2270f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/761a77e11e1e45c2a8b2d34d22cf8e04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7faabc484ce3666706c1beffda4bcfe2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/20/6d5c5416-d0b9-450c-9eb3-bd201d5993cd.png?resizew=150)
(3)【问题拓展】
小明继续探究:利用已有学习经验,尝试改变条件和结论位置,提出猜想:对于平面上的一点
![](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/e0520e9675bc1b416e8b8f01eb69fd13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5dc62e10004e73908091338362917da.png)
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名校
6 . 教材呈现:如图是华师版八年级上册数学教材第94页的部分内容.
请根据所给教材内容,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,
、
的垂直平分线分别交
于点
、
,垂足分别为
,
,已知
的周长为20,则
的长为__________.
(2)如图③,在
中,
,
,
、
分别是
、
上任意一点,若
,
,
,则
的最小值是__________.
2.线段垂直平分线 我们已经知道线段是轴对称图形,线段的垂直平分线是线段的对称轴.如图13.5.1,直线 ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() 线段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的距离相等. 已知:如图13.5.1, ![]() ![]() ![]() ![]() ![]() ![]() 分析 图中有两个直角三角形 ![]() ![]() ![]() |
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/20/449e0f3e-25f0-4b06-ba6d-cf363eed0870.png?resizew=741)
请根据所给教材内容,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
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
(2)如图③,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.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/b939af5ba06e279cce39396aaf0fae06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc34db5860990e51ba31edc8cdd077c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04ee826937d2add7a93aaa1422f8b736.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bb41f8ded9116e83f87a8e43b0ce7f8.png)
您最近一年使用:0次
名校
7 . 已知:
中,
,直线l是过点A的一条直线,点B、C在直线l同侧.
(1)如图1,若
,分别过点B、C作
于点D,
于点E,求证:
;
(2)如图2,若
,
,请探究
、
、
之间的数量关系,并证明;
(3)如图3,若
,
的垂直平分线
经过点A并交
于点E,且
,请求出
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/12/947c692c-e7f2-4efb-9b29-eecc01a01c2e.png?resizew=409)
(1)如图1,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb0a2d7d40a6c0bf1fddb802db381689.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6411dec63998be60c272d5367e84a6a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb773a664fa72fc5d8fe377e9f891901.png)
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7460e731038b553e169894d01ee6c5f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de9f93b9112f789d7353c670388675a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
(3)如图3,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63871d8b87f4ac0e024ca15fdb549b39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4059b5df01aed37dffdfb05bc4044c1.png)
您最近一年使用:0次
8 . 我们知道“在直角三角形中,30°角所对的直角边等于舒边的一半”这个定理.
感知:下面是这一定理的两种证明方法,请你选择一种加以证明.
已知在
中,
,
,求证:
.
方法一:如图1,在
上取一点
,使得
,连接
.
方法二:如图2,延长
到
,使得
,连接
.
你选择方法______;
探究:已知在
中,
,
,利用上述定理解决三个问题:
①如图①,
平分
交
于点
,求
和
的比.
结论![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5c477940379bd17e5cab8de00d189d3.png)
②如图②,
垂直平分
交
于点
,交
于点
,求
和
的比.
结论![](https://staticzujuan.xkw.com/quesimg/Upload/formula/826cd6cac67bb0aee9ee11d8e1e8910f.png)
③如图③,
于点
,求
和
的比.
结论![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aedec563e189f277aec55c6217244eb2.png)
其中错误的结论是______(填序号),请写出更正后的结论.
应用:如图3,两个全等的含有30°角的直角三角形拼成一个长方形
,
于点
,交
于点
,若
的面积是1,那么长方形
的面积是______.
感知:下面是这一定理的两种证明方法,请你选择一种加以证明.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/11/fc0813c7-6e09-414b-bfde-b0c53d269fab.png?resizew=341)
图1 图2
已知在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3018c687427b6257767eda4a8c6612.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebe44ff9f829f6c034682572ad00e366.png)
方法一:如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/feb67f27bcda7681b19239a199b4c4d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
方法二:如图2,延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a16dc02090b6e9263555061f14fbc8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
你选择方法______;
探究:已知在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3018c687427b6257767eda4a8c6612.png)
①如图①,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
结论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5c477940379bd17e5cab8de00d189d3.png)
②如图②,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
结论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/826cd6cac67bb0aee9ee11d8e1e8910f.png)
③如图③,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
结论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aedec563e189f277aec55c6217244eb2.png)
其中错误的结论是______(填序号),请写出更正后的结论.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/11/d2f609ed-436a-4f97-9ac2-1603b3d34009.png?resizew=289)
应用:如图3,两个全等的含有30°角的直角三角形拼成一个长方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d3f843b83e62bab294988a7ea134a63.png)
![](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/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12225a1a1eda07908309f8100cc34726.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/11/6f64b88c-ca46-4881-a13f-e92345dba329.png?resizew=147)
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9 . 求证:线段垂直平分线上的点与这条线段两个端点的距离相等.(已知,求证,证明,画图)
您最近一年使用:0次
2023-10-23更新
|
41次组卷
|
2卷引用:福建省龙岩市新罗区龙岩莲东中学2023-2024学年八年级上学期月考数学试题
10 . 用两种方法证明“直角三角形斜边上的中线等于斜边的一半”.
中,
,O为
的中点.
求证
.
证法1:延长
到点D,使
,连接
.
∵O为
的中点,
∴
_________(依据是_________).
∵
,
∴
垂直平分
.
∴
_________.
∴
.
请把证法1补充完整,并用不同的方法完成证法2.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
求证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7582af1fc3000103c72cbca34441542a.png)
证法1:延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f213621229843639780aae87fa29584.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
∵O为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40b54832529491611246a62c8475af52.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fe0cbc27f7482d769109b2b0def87cc.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c26a46e7879436d532af3f4b6e258a81.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7582af1fc3000103c72cbca34441542a.png)
请把证法1补充完整,并用不同的方法完成证法2.
您最近一年使用:0次