如图,矩形ABCD中,AB=4;AD=3,将矩形ABCD沿对角线AC折叠,点B落在点E处,B交CD于点F.
(1)求证△FAC为等腰三角形;
(2)求△FAC的面积.
(1)求证△FAC为等腰三角形;
(2)求△FAC的面积.
![](https://img.xkw.com/dksih/QBM/2021/5/11/2718551855628288/2790411265687552/STEM/2e5efb8d-15bc-40cd-b1ae-ebeada14f4f4.png?resizew=193)
更新时间:2021-08-20 20:09:09
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【推荐1】问题背景:
一次数学综合实践活动课上,小慧发现并证明了关于三角形角平分线的一个结论.如图1,已知
是
的角平分线,可证
.小慧的证明思路是:如图2,过点C作
,交
的延长线于点E,构造相似三角形来证明.
;
(2)基础训练:如图3,在
中,
,
是边
上一点.连接
,将
沿
所在直线折叠,点
恰好落在边
上的
点处.若
,
,则
的长;
(3)拓展升华:如图4,
中,
,
,
平分
,
的中垂线
交
延长线于点
,当
时,求
的长.
一次数学综合实践活动课上,小慧发现并证明了关于三角形角平分线的一个结论.如图1,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a02bad7fac070822f4c8b4f8b64bda72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b28971fe3e3f9d3849400e98b46fc3ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a02bad7fac070822f4c8b4f8b64bda72.png)
(2)基础训练:如图3,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca036d049f5205cf04cb1b9c5cd03f97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
(3)拓展升华:如图4,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a88d4e0249bd16d48eda01331d2d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8a7b5adfcac0f46a4cd19da4ebb4a2b.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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.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/9b407a788032149e5fc2fe7441c5aa80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
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【推荐2】如图,点E是△ABC的BC边上的一点,∠AEC=∠AED,ED=EC,∠D=∠B,求证:AB=AC.
![](https://img.xkw.com/dksih/QBM/2020/4/8/2436881561493504/2437520797843456/STEM/27be9b0af364455c99205bd38bfb6bd9.png?resizew=201)
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【推荐1】如图,矩形
中,E为
上一点,把
沿
翻折,点D恰好落在
边上的点F处.
(1)求证:
;
(2)若
,
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/1/f273b488-4878-42c8-be57-9665f375f479.png?resizew=156)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/884d06413db0b477e8aaf423467f5769.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c30e51d3170d01d7c227b71902e25626.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bdf82f2b3ac77ee7b9b35aebe0dd83f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
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【推荐2】在矩形
中,
,
,
.P为
上一点,将
沿直线
翻折至
的位置(点B落在点E处).
(1)如图,当点E落在边
上时,利用尺规作图,在图中作出
(不写作法,保留作图痕迹).
(2)在(1)的条件下,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/529188246973b6851b114466a238fc0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06ff2e2780c282e8ab8e5e88681e1efc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31919a6291edb861cfa0edd663b41c79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a855335176fc36a15017f50a8561348.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/099dd87a526391f830ac2a11e7d7ad56.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/1/13ce59ac-28d6-4327-b7bb-a00239b5162e.png?resizew=136)
(1)如图,当点E落在边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/099dd87a526391f830ac2a11e7d7ad56.png)
(2)在(1)的条件下,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
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【推荐1】【探究】:如图①,在矩形
中,点
是
的中点,将
沿
翻折得到
.连接
、
,
交
于点
.求证:
;
【应用】:如图②,在“探究”的条件下,连接
并延长,交
于点
,若
,
.
①求证:
;
②
.
![](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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad09a769a75b107390b9eeccc929f761.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b80d32bd31d565cd7a5fa4b42dc2e040.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa0e38c274227cbc24bda9ecb457ebfb.png)
【应用】:如图②,在“探究”的条件下,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/267ace52b64e1e7dfc5211e033255b7d.png)
①求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f42fb94a49181ea3d1f401a368add7f.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e09660e8bff0beac4eb769f8145e94b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/30/2d2c007f-f6b3-4607-bbfa-2cef948499ed.jpg?resizew=297)
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【推荐2】在学习矩形的过程中,小明遇到了一个问题:在矩形
中,如何用直尺和圆规解决把矩形的一角沿着过点A的直线折叠得到折叠
,使得
的顶点E在
边上,顶点F在
边上,点E是点D的对应点.他的思路是:首先以A为圆心
长为半径画弧交
边于点E,连接
,再作
的角平分线交
于点F,连接
,然后用全等三角形的知识使问题得到解决.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/31/8c4d3831-5b09-4604-80af-dcaf6007d8f3.jpg?resizew=190)
(1)请根据小明的思路完成下面的作图(保留作图痕迹,不写结论)
(2)证明:
在
和
中,
∵以A为圆心
长为半径画弧交
边于点E,
∴ ①.
∵
平分
,
∴ ②.
又 ③,
∴
( )④.
∴
是符合要求的折叠三角形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.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/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57e7106619c08f2bcc1d21f846e8a0de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/31/8c4d3831-5b09-4604-80af-dcaf6007d8f3.jpg?resizew=190)
(1)请根据小明的思路完成下面的作图(保留作图痕迹,不写结论)
(2)证明:
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/592849d99e570c23906687097b1072ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b66eae532e1a1551cfc7b5ff9cfc5aa9.png)
∵以A为圆心
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
∴ ①.
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57e7106619c08f2bcc1d21f846e8a0de.png)
∴ ②.
又 ③,
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c4f0763c0973e539a73198990d4bfc4.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
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【推荐1】如图,已知直线
交⊙O于A、B两点,
是
的半径,点C为
上一点,且
平分
,过C作
,垂足为D.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/16/319af784-9981-4248-9c8f-274d1d366eb4.png?resizew=153)
(1)求证:
为
的切线;
(2)若
,
的半径为10,求线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e61620a272dada8d4b9a9fab6379dfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07e37b122a7273e1251ea3860e74c896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9ccea461315a9d05aa0193b937d4bfe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74445ea89be7f9fcfafa402681d05ada.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73703e32dcae36b88c69dba1fcd84a4b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/16/319af784-9981-4248-9c8f-274d1d366eb4.png?resizew=153)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7af05da7275f22d658627b4958d86c97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88929f4ba0851730d5f941d426b87548.png)
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解答题-应用题
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【推荐2】图1为放在水平地面上的落地式话筒架实物图,图2为其示意图,支撑杆
垂直于地面,活动杆
固定在支撑杆上的点E处.若
,
,
,求活动杆端点D离地面的高度
.(结果精确到
,参考数据:
,
,
)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/30/9756edbe-1bcd-4f42-9b5a-f9dde36e35aa.png?resizew=157)
![](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/51c62558c45006d8830b72d31aae0c39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b000dd08b361a6bb345df9f85f05d22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76c147b148fa45cbe4ba5d0a8398e6b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84a3d448d4e52782ca2024411c5a11fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b517a427e371f90ced3cccce3abb26af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/589dfa98a450567b33b0f96b4c16d00e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/055ed3df1b9f8e8267f73e291e7e3356.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/30/9756edbe-1bcd-4f42-9b5a-f9dde36e35aa.png?resizew=157)
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