如图
,在矩形
中,
,连结对角线
,将线段
绕点
顺时针旋转
得到线段
,连结
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/26/4d29fecc-d08e-460b-8bf7-7269a94ed77a.png?resizew=182)
(1)若
,
,求
的长;
(2)如图
,连结
并延长,交直线
于点
,交直线
于点
.
当点
与点
重合时,求
的值;
若
,
,直接写出
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b9199a3de404cb13ae7710f73db5c8f.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/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/26/42e9fc17-c647-49f5-9842-ebdac443a6c0.png?resizew=127)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/26/4d29fecc-d08e-460b-8bf7-7269a94ed77a.png?resizew=182)
图1 图2
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d5a2cd05e4476fc72271e8fdb59a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
(2)如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fc56c77464a17a1e97b568762a3e2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e1c9ae241fd78126274c65e17990c88.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/0636e0c3ae734c1ac05ef4d53b1f2a92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c650fe55b7603f106c53ca2423451c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04ee826937d2add7a93aaa1422f8b736.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d0e770fc3239f58303af22ec57bb189.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
更新时间:2024-03-26 19:14:34
|
相似题推荐
解答题-证明题
|
较难
(0.4)
【推荐1】如图1,在△ABC中,AB=AC,点D为直线BC上一动点(不与点B,C重合),在AD的左侧作△ADE,使得AE=AD,∠DAE=∠BAC,连接BE.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/1/a7063318-d973-4428-9c1d-d06a27d55f20.png?resizew=110)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/1/adbd3e4d-a686-4d28-bc34-105c017656ec.png?resizew=164)
(1)当点D在线段BC上时,求证:△ABE≌△ACD.
(2)如图2,若
,BC=2.
①求△ABC的面积.
②在点D在运动过程中,若△ABE的最小角为25°,求∠EAC的度数.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/1/a7063318-d973-4428-9c1d-d06a27d55f20.png?resizew=110)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/1/adbd3e4d-a686-4d28-bc34-105c017656ec.png?resizew=164)
(1)当点D在线段BC上时,求证:△ABE≌△ACD.
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cccde778c619848076ea8c11b0b13a12.png)
①求△ABC的面积.
②在点D在运动过程中,若△ABE的最小角为25°,求∠EAC的度数.
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解题方法
【推荐2】(1)如图1,在四边形ABCD中,AB=AD,∠BAD=100°,∠B=∠ADC=90°.E,F分别是BC,CD上的点.且∠EAF=50°.探究图中线段EF,BE,FD之间的数量关系.
小明同学探究的方法是:延长FD到点G,使DG=BE,连接AG,先证明△ABE≌△ADG,再证明△AEF≌△AGF,可得出结论,他的结论是 (直接写结论,不需证明);
(2)如图2,若在四边形ABCD中,AB=AD,∠B+∠D=180°,E,F分别是BC,CD上的点,且2∠EAF=∠BAD,上述结论是否仍然成立,若成立,请证明,若不成立,请说明理由;
(3)如图3,四边形ABCD是边长为7的正方形,∠EBF=45°,直接写出△DEF的周长.
小明同学探究的方法是:延长FD到点G,使DG=BE,连接AG,先证明△ABE≌△ADG,再证明△AEF≌△AGF,可得出结论,他的结论是 (直接写结论,不需证明);
(2)如图2,若在四边形ABCD中,AB=AD,∠B+∠D=180°,E,F分别是BC,CD上的点,且2∠EAF=∠BAD,上述结论是否仍然成立,若成立,请证明,若不成立,请说明理由;
(3)如图3,四边形ABCD是边长为7的正方形,∠EBF=45°,直接写出△DEF的周长.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/31/58344d70-cafb-4d70-9661-c45df55ceffd.png?resizew=382)
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较难
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【推荐1】如图,在平行四边形ABCD中,AF平分∠BAD交CD点F,BG平分∠ABC交CD点G,AF与BG交于点E.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/19/b688e1f2-4db0-4b0c-bcee-3affa06b0903.png?resizew=188)
(1)求证:DG=CF;
(2)若AB=10,AD=6,AF=8,求FG和BG的长度.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/19/b688e1f2-4db0-4b0c-bcee-3affa06b0903.png?resizew=188)
(1)求证:DG=CF;
(2)若AB=10,AD=6,AF=8,求FG和BG的长度.
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【推荐2】已知
是以CD为斜边的等腰直角三角形.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/4/c191eaa5-7c2a-4001-b54a-15c9c783994d.png?resizew=565)
(1)如图1,直线l过点P,过点D、C分别作直线l的垂线,垂足为点A、B,求证:
.
(2)如图2,P为线段AB的中点,连接AD、BC,若
,求证:
.
(3)在(2)的条件下,连接AC,若AC平分
,
,求AB的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5dc6b0f69ed7e3633248f6b1c093e874.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/4/c191eaa5-7c2a-4001-b54a-15c9c783994d.png?resizew=565)
(1)如图1,直线l过点P,过点D、C分别作直线l的垂线,垂足为点A、B,求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/880c83be599118eb113011033709dfc7.png)
(2)如图2,P为线段AB的中点,连接AD、BC,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05d35d8d8bb0dc17f2f86fe5b230a2b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7099026716ee1821dd7d9f157dc055f5.png)
(3)在(2)的条件下,连接AC,若AC平分
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4189a0821a0ffab9dc171ecd279ba442.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a88c44f558705de3bcefcfc0ece96b8f.png)
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解答题-问答题
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(0.4)
【推荐3】综合与实践:
问题情境:数学课上,小王和小东两位同学利用三角板操作探究图形.
操作探究1:小王将两块全等的含
角的直角三角板按如图①方式在平面内放置,其中两锐角顶点重合于点
,
.已知
长
,则点
、
之间的距离为 .(写出具体解答过程)
操作探究2:小东将两块全等的含
角的直角三角板按如图②方式在平面内放置.其中两个
角顶点重合于点
,
与
重合,已知
长
,请你帮小东同学求出此对点
、
之间的距离;
操作探究3:随后,小王将图②中的
换成了含
角的三角板,同样是顶点重合于点
,
与
重合,已知直角边
与
长均为
,他还想求点
,
之间距离,你能求出此时点
,
之间的距离吗?
问题情境:数学课上,小王和小东两位同学利用三角板操作探究图形.
操作探究1:小王将两块全等的含
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79a97bb4dcfab4ec7539bc783d563c49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80b1fe1b971b780e443a9b13621611c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
操作探究2:小东将两块全等的含
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80b1fe1b971b780e443a9b13621611c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
操作探究3:随后,小王将图②中的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79a97bb4dcfab4ec7539bc783d563c49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.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/80b1fe1b971b780e443a9b13621611c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
您最近一年使用:0次
解答题-问答题
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较难
(0.4)
【推荐1】【结论提出】:三角形的角平分线分对边所成的两条线段的比等于夹这个角的两条边的比.
(1)【思路说明】已知:如图1,
中,
平分
交
于D.试说明:
.理由:过点C作
,交BA延长线于点E,易得
______,由
,
平分
可得
______,代入上式得
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/d2a539fb-1170-4fec-8905-4f4ba3bc2b84.png?resizew=154)
(2)【直接应用】如图2,
中,
,
平分
交
于D,若
,在不添加辅助线的情况下直接写出
______.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/18356efa-738e-4fb4-aefd-395062ce1771.png?resizew=145)
(3)如图3,若四边形
为矩形,
,将
沿
翻折得到
,延长
、
分别交
于M、H两点,当
时.
①求
的长;
②直接写出
______;
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/d7f22b90-8f9a-4862-ad53-ae5e73082329.png?resizew=157)
(4)【拓展延伸】如图4,若四边形
是边长为6的菱形,
,当点E为
边的三等分点时,将
沿
翻折得到
,直线
与
所在直线交于点P、与
所在直线交于点Q,请直接写出
的长______.
(1)【思路说明】已知:如图1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ead64391e42f81943e500aed314e4b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aec5d3a183594be47dd6e386d2c9d725.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94df6f27d5eb3bf395eb51c8de099342.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aec5d3a183594be47dd6e386d2c9d725.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/32217457c4e96e2ef155cf15c1b65d97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ead64391e42f81943e500aed314e4b4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/d2a539fb-1170-4fec-8905-4f4ba3bc2b84.png?resizew=154)
(2)【直接应用】如图2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1777acc5d9f9195b2d1b474a504766f2.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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca94096b018dec79e6a266ba6cdf998f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c26a46e7879436d532af3f4b6e258a81.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/18356efa-738e-4fb4-aefd-395062ce1771.png?resizew=145)
(3)如图3,若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0decd4311730d690c18b2639265c785b.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/ca2698f08d94afa1cd5b81444791f4c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/374fe9986ebbc986fc422e514ab93a51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a95d946287c2b3e5f4ec5ee1b1f2e970.png)
①求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdae78f4d3b8d8213ac3ac9a9567eb5.png)
②直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1f4324388f1e4b83d4a4dace32766d9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/d7f22b90-8f9a-4862-ad53-ae5e73082329.png?resizew=157)
(4)【拓展延伸】如图4,若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.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/ca2698f08d94afa1cd5b81444791f4c7.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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/426ea707-bd4d-43a9-9af9-24f7b760a781.png?resizew=303)
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解答题-证明题
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较难
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【推荐2】【观察与猜想】
(1)如图1,点
是矩形
内一点,过点
的直线
,分别交矩形的边为点
.若
,则
______;
【类比探究】
(2)如图2,在平行四边形
中,点
分别在边
上,连接
与
交于点
.求证:
;
【拓展延伸】
(3)如图3,在四边形
中,
,
在边
上,连接
与
交于点
,当
时,求
的值.
(1)如图1,点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44b0e8d6874ca0163575176a49accf45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fab542c9358d2256f482066a50ec674.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32672aa4900a994c7c812dfc74ef1e45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a2b3247afa684b10c8e1da99cf33d5b.png)
【类比探究】
(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/e6e55ab3f372d8b5034677bd779b4218.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4515e1dff9a852b3294dc1d6488a5748.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a424b50eaeafa6f302ffd95476cb86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36f303f08c73f05991f79095160dfe30.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3de7b55161ecadf3c2172a74cd48bd0b.png)
【拓展延伸】
(3)如图3,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d91cc5f25788922663a87fa5ca9fe7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.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/15a424b50eaeafa6f302ffd95476cb86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4da923ec4f440dfd368a94cd822beb58.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e5a3686345cde38f6832b9c686f37ef.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/23/52263a67-e61d-42e6-a2f6-23988a8fa1dd.png?resizew=410)
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较难
(0.4)
名校
【推荐1】【阅读】定义:如果一个三角形一条边上的高与这条边的比值是4:5,那么称这个三角形为“准黄金”三角形,这条边就叫做这个三角形的“金底”.
【理解】(1)如图1,在△ABC中,AC=8,BC=5,∠ACB=30°,试判断△ABC是否是“准黄金”三角形,请说明理由.
【应用】(2)如图2,△ABC是“准黄金”三角形,BC是“金底”,把△ABC沿BC翻折得到△DBC,AD交BC的延长线于点E,若点C恰好是△ABD的重心,求
的值.
【拓展】(3)如图3,a∥b,且直线a与b之间的距离为4,“准黄金”△ABC的“金底”BC在直线b上,点A在直线a上,
=
,若∠ABC是钝角,将△ABC绕点C按顺时针方向旋转得到△A′B′C,线段A′C交a于点D.当点B′落在直线b上时,求
的值.
【理解】(1)如图1,在△ABC中,AC=8,BC=5,∠ACB=30°,试判断△ABC是否是“准黄金”三角形,请说明理由.
【应用】(2)如图2,△ABC是“准黄金”三角形,BC是“金底”,把△ABC沿BC翻折得到△DBC,AD交BC的延长线于点E,若点C恰好是△ABD的重心,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2465ee1fec12351943f15055dfd6ec73.png)
【拓展】(3)如图3,a∥b,且直线a与b之间的距离为4,“准黄金”△ABC的“金底”BC在直线b上,点A在直线a上,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2465ee1fec12351943f15055dfd6ec73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c98ee8ce2c56dccae6b63b5a9ca022b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61f9215613b7b05217ed77268c238391.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/fff2759a-68cf-49c4-aef8-0af02b3dd63b.png?resizew=557)
您最近一年使用:0次
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真题
【推荐2】如图,在矩形ABCD中,AB=6cm,AD=8cm.点P从点B出发,沿对角线BD向点D匀速运动,速度为4cm/s,过点P作PQ⊥BD交BC于点Q,以PQ为一边作正方形PQMN,使得点N落在射线PD上,点O从点D出发,沿DC向点C匀速运动,速度为3cm/s,以O为圆心,0.8cm为半径作圆O,点P与点O同时出发,设它们的运动时间为t(单位:s)(0<t<
)
(1)如图1,连接DQ,当DQ平分∠BDC时,t的值为
(2)如图2,连接CM,若△CMQ是以CQ为底的等腰三角形,求t的值;
(3)请你继续连行探究,并解答下列问题:
①证明:在运动过程中,点O始终在QM所在直线的左侧;
②如图3,在运动过程中,当QM与圆O相切时,求t的值;并判断此时PM与圆O是否也相切?说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a391005600bdd69c96750589f9adb048.png)
(1)如图1,连接DQ,当DQ平分∠BDC时,t的值为
(2)如图2,连接CM,若△CMQ是以CQ为底的等腰三角形,求t的值;
(3)请你继续连行探究,并解答下列问题:
①证明:在运动过程中,点O始终在QM所在直线的左侧;
②如图3,在运动过程中,当QM与圆O相切时,求t的值;并判断此时PM与圆O是否也相切?说明理由.
![](https://img.xkw.com/dksih/QBM/2018/1/6/1854665805488128/1855382840188928/STEM/8a0a76de0dad44e5b3665c420fe6eb21.png?resizew=431)
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