名校
1 . 如图,海中有两个岛C、D,某渔船在海中的A处测得小岛D位于东北方向上,且相距
海里,该渔船自西向东航行一段时间到达B处,此时测得小岛C恰好在点B的正北方向上,且相距75海里,又测得点B与小岛D相距
海里.
(1)求sin∠ABD的值;
(2)求小岛C、D之间的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/578aebcec4f8ab25124f67eaf5b368a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee6c20baf6a33c1ff52cc51516c7e192.png)
(1)求sin∠ABD的值;
(2)求小岛C、D之间的距离.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/29/e969c358-6fe2-424a-be82-49001e0078de.png?resizew=127)
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2021-01-01更新
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4卷引用:重庆市第八中学校2020-2021学年九年级第一学期定时训练二数学试题
重庆市第八中学校2020-2021学年九年级第一学期定时训练二数学试题四川省达州市通川区第一中学校2020-2021学年九年级上学期12月月考数学试题(已下线)2022年四川省泸州市中考数学真题变式题21-25题四川省达州市通川区蒲家中学校2022-2023学年九年级上学期第三次月考数学试题
2 . 如图,面积为16的菱形ABCD中,点O为对角线的交点,点E是边BC的中点,过点E作
于点F,
于点G,则四边形EFOG的面积为__ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c672f693a7e75a7bae4936dcb1920430.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/827beb23a9fe02a8b588645bcb82ce67.png)
![](https://img.xkw.com/dksih/QBM/2020/12/25/2621717454282752/2623998510923776/STEM/c1b729124abc45d9911a62de0f9f5321.png?resizew=202)
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2020-12-28更新
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371次组卷
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5卷引用:辽宁省沈阳市铁西区、浑南区2020-2021学年九年级上学期期末数学试题
辽宁省沈阳市铁西区、浑南区2020-2021学年九年级上学期期末数学试题(已下线)考点17 矩形、菱形、正方形(考点专练)-备战2021年中考数学考点微专题(已下线)专题18.8 菱形(专项练习)-2020-2021学年八年级数学下册基础知识专项讲练(人教版)(已下线)专题6.6 三角形的中位线(专项练习)-2020-2021学年八年级数学下册基础知识专项讲练(北师大版)辽宁省沈阳市铁西区大青实验学校2022-2023学年九年级上学期期末数学试题
3 . 如图,
的对角线
,
相交于点O,且
,
,
.
![](https://img.xkw.com/dksih/QBM/2020/12/9/2617043781959680/2621276023365632/STEM/ee7a0951-e4ce-4583-a180-a4f564070f94.png?resizew=183)
(1)求证:四边形
是菱形
(2)若
,
,求
的长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a78e006003b83147e901b34688a7f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7acc0628dabbbaa929b7437021cad8a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cede2006bf19da5ae1c126da517ce79c.png)
![](https://img.xkw.com/dksih/QBM/2020/12/9/2617043781959680/2621276023365632/STEM/ee7a0951-e4ce-4583-a180-a4f564070f94.png?resizew=183)
(1)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7cbfaec1d9dcaaf159b060163436113.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
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4 . 如图1所示是放置在水平桌面上的台灯,图2是其侧面示意图,其中底座的示意图为矩形EFGB,EF=2.5cm,
,灯罩
,灯臂与底座构成的
可以绕点C下调节一定的角度.使用发现:当CD平线上方且与水平线所成的角为
时,台灯光线最佳,则将台灯调整到光线最佳时点D到桌面FG的距离为________________
(参考数据:
取1.732,结果精确到0.1cm)
![](https://img.xkw.com/dksih/QBM/2020/12/8/2616188635512832/2621204222017536/STEM/a59025c4-46ca-4317-bd82-0d17afdd000a.png?resizew=177)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f07dcd2a20048a6530c54fc1377702d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d88e3f81f2ed1c0251ee8e926ef7463b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec94e7ff23e7ea3ae4b5c6e421f56e68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ac09dc1ca2cdd7aef28c218763d3e4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0980ab28d4ee04e238f8623dcd4836f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://img.xkw.com/dksih/QBM/2020/12/8/2616188635512832/2621204222017536/STEM/a59025c4-46ca-4317-bd82-0d17afdd000a.png?resizew=177)
![](https://img.xkw.com/dksih/QBM/2020/12/8/2616188635512832/2621204222017536/STEM/d38478b998254729b618ed0a4c9606c9.png?resizew=130)
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解题方法
5 . 定义:有且仅有一组对角相等的凸四边形叫做“准平行四边形”.例如:凸四边形
中,若
,
,则称四边形
为准平行四边形.
(1)如(图①),
、
、
、
是⊙O上的四个点,
,延长
到
,使
.求证:四边形
是准平行四边形;
(2)如(图②),准平行四边形
内接于⊙O,
,
,若⊙O的半径为5,
,求
的长;
(3)如(图③),在
中,
,
,
,若四边形
是准平行四边形,且
,请直接写出
长的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1393308bc68322f50fa29702dd412263.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/520d831f0b99a1698f06775cc2047390.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/19/d5772f9f-aed7-44d3-80fd-1dc49570c3cc.png?resizew=381)
(1)如(图①),
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/991fdca41f19de62f60e293c3756aee0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/045b85674bbe01e477c76501affed905.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79ba22b69231ffb2878458c15c51bd90.png)
(2)如(图②),准平行四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c06e36ec59fa93ac857e35796a4b8311.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4009aa13093cc3865dcd51b371892160.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a88d4e0249bd16d48eda01331d2d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
(3)如(图③),在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.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/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5755afc235f06b6a6c8624aaa0a6aa5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
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2020-12-24更新
|
535次组卷
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7卷引用:专题18创新型与新定义综合问题-决胜2020年中考数学压轴题全揭秘精品(2)
(已下线)专题18创新型与新定义综合问题-决胜2020年中考数学压轴题全揭秘精品(2)江苏省扬州市仪征市2019-2020学年九年级上学期期末数学试题江苏省南通市如东县2019-2020学年九年级上学期期中数学试题湖南省长沙市周南教育集团2020-2021学年九年级上学期12月联考数学试题湖南长沙周南集团2019-2020学年九年级下学期第三次联考数学试题(已下线)必刷卷02-2021年中考数学考前信息必刷卷(湖南长沙专用)江苏省扬州市江都区八校联谊2022-2023学年九年级数学上学期期中试题
名校
6 . 如图,矩形ABCD和矩形CEFG,AB=1,BC=CG=2,CE=4,点P在边GF上,点Q在边CE上,且PF=CQ,连结AC和PQ,M,N分别是AC,PQ的中点,则MN的长为___ .
![](https://img.xkw.com/dksih/QBM/2020/12/14/2613977862430720/2614228560125952/STEM/9eef3d0970ae4778b76ce574ede22dc6.png?resizew=174)
您最近一年使用:0次
2020-12-24更新
|
356次组卷
|
4卷引用:浙江省温州育英2020--2021学年八年级上学期11月月考数学试题
浙江省温州育英2020--2021学年八年级上学期11月月考数学试题(已下线)专题21 填空题压轴题之几何综合计算-备战2022年中考数学临考题号押题(全国通用)(已下线)【新东方】【2021.5.19】【SX】【初二下】【初中数学】【SX00010】2022年河南省郑州市九年级中考二模模拟数学试题卷
7 . 下表所示的是小安填写的数学实践活动报告的部分内容.
已知四边形
为矩形,
于点G,且点A,B,C,D,E,F,G都在同一竖直平面内,求铁塔
的高度.(结果精确到1米;参考数据:
)
题目 | 测量铁塔顶端到地面的高度 | |
测量目标示意图 | ||
相关数据 |
|
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce50eeb654ef50f36a582c785f273ecf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7c57b07f75e97d9f84718bd495ebcf4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57c0924cc4f92785c425706d79f28cfd.png)
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8 . 如图,在长方形纸片
中,
,
,将长方形纸片折叠,使点
落在
边的点
处,折痕为
,此时
.
(1)求
的值;
(2)在
边上是否存在一个动点
,且不与点
、
重合,使
的周长最小.如果存在求出
的周长最小值:如果不存在,请说明理由;
(3)若点
,
是
边上的两个动点,且不与点
,
重合,
.当四边形
的周长最小时,其周长的最小值是______.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bdf82f2b3ac77ee7b9b35aebe0dd83f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e0f73b3c63084d9c032802e01f9a168.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/438f34bc8b04e8c494b91306ac6fe352.png)
(2)在
![](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/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eadb6f330e2d5325adb08c2b1d80b1ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eadb6f330e2d5325adb08c2b1d80b1ae.png)
(3)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcad23fd44f0c58d0def5a6ddf22e61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcb3465d2beda0240e452d25501316bd.png)
![](https://img.xkw.com/dksih/QBM/2020/11/10/2592786583642112/2607572504625152/STEM/ae4eb504-5376-443c-947f-649da94572cf.png)
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名校
9 . 如图,在四边形
中,
,
,
,若
,
,则点
到
的距离是______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bf10d92f20501e19d25f6f4159aab89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/212bfbd5575772ca36d6fc3e7b246e49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efc6e4b936d7a800e839a30c3839574d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7aeb2a8d1437eeb4482c3b6ad9f315.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/2020/11/11/2590564564615168/2605359084453888/STEM/ede9fd48317141fe94381cd163b6f1de.png?resizew=190)
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2020-12-02更新
|
646次组卷
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3卷引用:江苏省南京市第二十九中学2020-2021学年八年级上学期期中数学试卷题
江苏省南京市第二十九中学2020-2021学年八年级上学期期中数学试卷题江苏省南京市联合体2020-2021学年第一学期八年级上数学期中考试试卷(已下线)专题14全等三角形-备战2021年中考数学核心考点清单(江苏专用)
10 . 如图,▱ABCD中,点E是BC的中点,连接AE并延长交DC延长线于点F.
(1)求证:CF=AB;
(2)连接BD、BF,当∠BCD=90°时,求证:BD=BF.
(1)求证:CF=AB;
(2)连接BD、BF,当∠BCD=90°时,求证:BD=BF.
![](https://img.xkw.com/dksih/QBM/2020/11/20/2596768154419200/2599885401030656/STEM/d0862373f8ca4e508a9168040c6a6c3b.png?resizew=167)
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2020-11-24更新
|
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3卷引用:2020年湖北省潜江市张金中学中考数学模拟试卷(6月份)
2020年湖北省潜江市张金中学中考数学模拟试卷(6月份)(已下线)专题12.2 矩形菱形和正方形(2)-备战2021年中考数学精选考点专项突破题集(全国通用)2023年浙江省丽水市庆元县江根乡中学中考一模数学试题