如图,已知
为等边三角形,在
上取一点
(与点
、
不重合),以
为边向外作等边
,连接
、
,再分别以
、
为边向外作等边
和等边
,连接
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/11/787fe7a0-aa3c-4dac-9bab-e6ed07d9b480.png?resizew=179)
(1)求证:
;
(2)记
、
、
、
的面积分别为
、
、
、
,则这四个面积之间存在怎样的数量关系式?说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d631f45bc652539853f236952afa5bbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.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/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ff39c7aa648afd1080206c8080ff79e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00870385ca7f3214e2971779eb4c7904.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e72b2e1ff83e95df048745322982451.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/11/787fe7a0-aa3c-4dac-9bab-e6ed07d9b480.png?resizew=179)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00ad3ed5548d3020172694c701507d99.png)
(2)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcb49df05f2e31d005735c3f14a21d30.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00870385ca7f3214e2971779eb4c7904.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ff39c7aa648afd1080206c8080ff79e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6899bf9cadae2ccdb14cbc87d4f280ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f30f56664446f32dbbc2c5f12a99374.png)
2024八年级·全国·竞赛 查看更多[2]
更新时间:2024-03-04 14:21:17
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相似题推荐
解答题-问答题
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较难
(0.4)
【推荐1】在
中,
,
,
.点D是
边上一点(点D不与点C重合),连接
.在
的右侧作等腰直角
,使
,
,连接
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/11/181805c8-ca22-48da-984b-7f501d655a61.png?resizew=407)
(1)如图①,若
,求线段
的长;
(2)在图②中
___________度,线段
的长为___________(直接填空);
(3)作
的角平分线交
于点F,直接写出线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b27e47690ed332c573186992b6d25654.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c14a66ed4bd66df65bc42c4ac1ed15c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dae8221601c7bd5c51fd520615581fa1.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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7c50d6d16f99c65005dfb950c30d760.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d212c1709b8e72a055cf1b5381ef64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/348fb71fbc47fd87e9ce011652ef4186.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/11/181805c8-ca22-48da-984b-7f501d655a61.png?resizew=407)
(1)如图①,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fc13fe21e64d9b45614ed43be847904.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
(2)在图②中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcfbc2a377c4d6c0423744c3b63409b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
(3)作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57e7106619c08f2bcc1d21f846e8a0de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
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名校
【推荐2】在△ABC中,AB=AC=BC,∠ACB=∠ABC=∠BAC=60°,点E是直线AB上一点,连接CE,以CE为边作等边三角形CDE,(C、D、E按逆时针方向排列),连接AD.点F在直线BC上,连接EF,使EF=EC.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/15/24f5278d-e82a-4000-8bf2-6c05f3eabbc3.png?resizew=685)
(1)如图1,当点E在线段AB上时,判断△BCE与△ACD的关系 并猜想线段AD与BC的位置关系 ;(直接写出结论,不需证明)
(2)如图2,当点E在BA的延长线上时,猜想线段AD与BC的位置关系,并说明理由;
(3)当∠EFC=25°时,请直接写出∠ADE的度数________.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/15/24f5278d-e82a-4000-8bf2-6c05f3eabbc3.png?resizew=685)
(1)如图1,当点E在线段AB上时,判断△BCE与△ACD的
(2)如图2,当点E在BA的延长线上时,猜想线段AD与BC的位置关系,并说明理由;
(3)当∠EFC=25°时,请直接写出∠ADE的度数________.
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解答题-问答题
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较难
(0.4)
【推荐1】在平面直角坐标系中,直线
分别与x轴和y轴交于A、B两点.
(1)如图1,点C是线段AB上的一动点,连结OC,若将线段OC绕点O顺时针旋转90°得到线段OD,求当点C从点B运动到A的过程中,线段OD扫过的面积;
(2)如图2,以点B为圆心2为半径作
,设点C为
上的一动点,连结OC,若将线段OC绕点O顺时针旋转90°得到线段OD,连结BD,求BD长的最大值和最小值,并写出相应点D的坐标;
(3)如图3,线段
,点C是以点F为圆心1为半径的
上的一个动点,连结EC,以EC为边在EF的上方作等边三角形
,求
面积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/812eed46a589bde8b7c78a81a8cf9b9a.png)
(1)如图1,点C是线段AB上的一动点,连结OC,若将线段OC绕点O顺时针旋转90°得到线段OD,求当点C从点B运动到A的过程中,线段OD扫过的面积;
(2)如图2,以点B为圆心2为半径作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6f6558fef858bf27e9811c2d9426fe7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6f6558fef858bf27e9811c2d9426fe7.png)
(3)如图3,线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aeedb5f361a1baff6338436fff6c471d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/989dc4af481c6133824200942b9e5c8d.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72cb97395ebc5ee1b212afb7a97b985c.png)
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【推荐2】如图1,D、E、F是等边三角形ABC中不共线三点,连接AD、BE、CF,三条线段两两分别相交于D、E、F.已知AF=BD,∠EDF=60°.
![](https://img.xkw.com/dksih/QBM/2021/11/9/2847354454622208/2848040332181504/STEM/f05f2fe0-cc65-4963-b3e5-d9710f1d1562.png)
(1)证明:EF=DF;
(2)如图2,点M是ED上一点,连接CM,以CM为边向右作△CMG,连接EG.若EG=EC+EM,CM=GM,∠GMC=∠GEC,证明:CG=CM.
(3)如图3,在(2)的条件下,当点M与点D重合时,若CD⊥AD,CF=5,GD=4,请问在△ACD内部是否存在点P使得P到△ACD三个顶点距离之和最小,若存在请直接写出距离之和的最小值;若不存在,试说明理由.
![](https://img.xkw.com/dksih/QBM/2021/11/9/2847354454622208/2848040332181504/STEM/f05f2fe0-cc65-4963-b3e5-d9710f1d1562.png)
(1)证明:EF=DF;
(2)如图2,点M是ED上一点,连接CM,以CM为边向右作△CMG,连接EG.若EG=EC+EM,CM=GM,∠GMC=∠GEC,证明:CG=CM.
(3)如图3,在(2)的条件下,当点M与点D重合时,若CD⊥AD,CF=5,GD=4,请问在△ACD内部是否存在点P使得P到△ACD三个顶点距离之和最小,若存在请直接写出距离之和的最小值;若不存在,试说明理由.
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【推荐1】在锐角△ABC中,AB=AC,以AB为直径的⊙O分别交边 BC,AC于点D,E,AF⊥DE于点F.
![](https://img.xkw.com/dksih/QBM/2021/4/14/2699721801637888/2702496883589120/STEM/69683fed-1c8e-45dd-a0a2-b14741c4b76e.png)
(1)求证:∠EDC=2∠CAF;
(2)若AB=BC,判断直线AF与⊙O的位置关系,并说明理由;
(3)若
,求
的值.
![](https://img.xkw.com/dksih/QBM/2021/4/14/2699721801637888/2702496883589120/STEM/69683fed-1c8e-45dd-a0a2-b14741c4b76e.png)
(1)求证:∠EDC=2∠CAF;
(2)若AB=BC,判断直线AF与⊙O的位置关系,并说明理由;
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e86e01664e2a09bc20fba03cc394999.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2465ee1fec12351943f15055dfd6ec73.png)
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【推荐2】如图,直线
与x轴、y轴分别交于点A和点B,点C在线段
上,将
沿
所在直线折叠后,点A恰好落在y轴上点D处,若
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/21/06fa601f-677a-4f75-a2c3-bc62a89622ca.png?resizew=343)
(1)求直线
的解析式.
(2)求
的值.
(3)直线CD上是否存在点P使得
,若存在,请直接写出P的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c15fb18163df0690365a0d2e7ee88f5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07e37b122a7273e1251ea3860e74c896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6e3dfcd8aff269dd5aba398816490c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90bd1ffa355edcdc023b5a6b47ca7526.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/21/06fa601f-677a-4f75-a2c3-bc62a89622ca.png?resizew=343)
(1)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bde7cda4524748283f32f91e534afaf.png)
(3)直线CD上是否存在点P使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06921683511d4123eb54086539e9c1c8.png)
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