如图,在四边形ABCD中,AD∥BC,∠ABC=∠ADC=90°,对角线AC、BD交于点O,DE平分∠ADC交BC于点E,连接OE.
(2)若∠BDE=15°,求∠EOC的度数;
(3)在(2)的条件下,若AB=2,求矩形ABCD的面积.
(2)若∠BDE=15°,求∠EOC的度数;
(3)在(2)的条件下,若AB=2,求矩形ABCD的面积.
21-22八年级下·江苏盐城·阶段练习 查看更多[11]
江苏省盐城市亭湖区毓龙路实验学校2021-2022学年八年级下学期3月月考数学试题(已下线)专题9.12 矩形(知识讲解)-2022-2023学年八年级数学下册基础知识专项讲练(苏科版)(已下线)专题9.30 中心对称图形——平行四边形(全章复习与巩固)(巩固篇)(专项练习)-2022-2023学年八年级数学下册基础知识专项讲练(苏科版)(已下线)专题9.28 中心对称图形——平行四边形(全章复习与巩固)(知识讲解)-2022-2023学年八年级数学下册基础知识专项讲练(苏科版)(已下线)第18章 平行四边形 单元综合检测(重点)(练习)-2022-2023学年八年级数学下册同步精品课堂(人教版)(已下线)专题18.26 矩形(知识讲解)-2022-2023学年八年级数学下册基础知识专项讲练(人教版)(已下线)22.3.1.2 矩形的判定-2022-2023学年八年级数学下册《考点·题型·技巧》精讲与精练高分突破系列(沪教版)(已下线)专题5.1 矩形(知识讲解)-2022-2023学年八年级数学下册基础知识专项讲练(浙教版)江苏省徐州市运河中学2023-2024学年八年级下学月考数学试题(已下线)第06讲 矩形(3大考点+9种题型+强化训练)-【帮课堂】2023-2024学年八年级数学下册同步学与练(苏科版)(已下线)考题猜想05 八年级期中必刷题(拔高必刷58题21种题型)-2023-2024学年八年级数学下学期期中考点大串讲(苏科版)
更新时间:2022-09-04 13:07:53
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【推荐1】【数学阅读】在数学课上,老师出了这样一个有趣的数学问题:如图
,直线
,现想在直线
、
之间作一条直线
平行于直线
、
,并且使直线
上的点到直线
、
之间的距离相等.小明做了如下操作:分别作
、
的平分线交于点
,过点
作直线
、
的平行线,过点
分别作直线
、
、
的垂线,垂足分别为
、
、
,此时直线
上的点到直线
、
的距离相等.
![](https://img.xkw.com/dksih/QBM/2021/1/7/2631170953043968/2634513230012416/STEM/b745eb5f-4c74-4a57-a3ff-0ad54a9e5e57.png)
【知识运用】
(1)试说明:
;
【理解应用】
(2)若
,
,直线
交
于点
.试问
的度数为 ,
是 三角形;
周长为 ;
【问题迁移】
(3)若点
是射线
上的一个动点(不包括端点).如图
,连接
,将
折叠,顶点
落在点
处,若
,点
刚好落在其中的一条平行线上,试求
的度数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10df84d553a8826a7ce9bff4bf0d95b9.png)
![](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/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](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/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](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/ea2ee75a234ac05a3225e49ddd8c5065.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6c19410c7abeae002ca97cfad4c791f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](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/895dc3dc3a6606ff487a4c4863e18509.png)
![](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/49b50357a6545cae8348e3059312f520.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/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://img.xkw.com/dksih/QBM/2021/1/7/2631170953043968/2634513230012416/STEM/b745eb5f-4c74-4a57-a3ff-0ad54a9e5e57.png)
【知识运用】
(1)试说明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e122ff01fd1d47bd0e36a3c8aafcd6b0.png)
【理解应用】
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0130a3f2964c376d869156718838cd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ae8a560832989c416096a7897bbc419.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7d6902c8862bd2616be038549f77aff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00505ead283d9f38634f32aa2ed393b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00505ead283d9f38634f32aa2ed393b6.png)
【问题迁移】
(3)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccaee8f228ff24e7c89879bb5b999cf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fb26d84907c923278ac4626a9d58947.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c8a8f63088245653535d5d23d6f26a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c01e513851b74a20876528431bb85ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d19304561bed6d1da08860a4ccfa714.png)
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【推荐2】如图1,在边长为6的等边△ABC中,点D从点A开始在射线AB上运动,速度为1个单位/秒,点F同时从C出发,以相同的速度沿射线BC方向运动,过点D作DE⊥AC,连接DF交射线AC于点G,设点D的运动时间为t秒;
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/ee0a009c-e384-49c4-b8b3-eab925d24c7c.png?resizew=383)
(1)当DF⊥AB时,求t的值;
(2)当点D在线段AB上运动时,是否始终有DG=GF?若成立,请说明理由;
(3)小扬同学通过测量发现,当点D在线段AB上时,EG的长始终等于AC的一半,他想当点D运动到图2的情况时,EG的长是否发生变化?若改变,说明理由;若不变,求出EG的长.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/ee0a009c-e384-49c4-b8b3-eab925d24c7c.png?resizew=383)
(1)当DF⊥AB时,求t的值;
(2)当点D在线段AB上运动时,是否始终有DG=GF?若成立,请说明理由;
(3)小扬同学通过测量发现,当点D在线段AB上时,EG的长始终等于AC的一半,他想当点D运动到图2的情况时,EG的长是否发生变化?若改变,说明理由;若不变,求出EG的长.
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【推荐1】如图,在
中,
、
分别是
、
的中点,连接
并延长
至点
,使
,连接
.
(1)求证:四边形
是平行四边形;
(2)探究:当
满足什么条件时,四边形
是矩形,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9a9618018d717926540d1452f76e44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
(1)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d15047493914a7de990b3b905875436.png)
(2)探究:当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94a5a2949b3d520ed03d57126c7d4d8d.png)
![](https://img.xkw.com/dksih/QBM/2021/10/4/2821962404356096/2825511653359616/STEM/e46110608de1492ea94b4d7141fa63c4.png?resizew=139)
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【推荐2】已知:如图,在平行四边形
中,
,E、F分别是边
和
的中点,连接
,
.求证:四边形
是矩形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](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/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
![](https://img.xkw.com/dksih/QBM/2020/12/31/2626245191974912/2630472595816448/STEM/c6657fe8-a42a-4a90-a010-c605bd0c0c14.png)
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【推荐3】下面是小东设计的“利用直角三角形和它的斜边中点作矩形”的尺规作图过程.
已知:如图,在Rt△ABC中,∠ABC=90°,O为AC的中点.
![](https://img.xkw.com/dksih/QBM/2022/1/26/2903002187677696/2903548966772736/STEM/2e98e29ade694734ae2387c1d9122746.png?resizew=139)
求作:四边形ABCD,使得四边形ABCD是矩形.
作法:①作射线BO,以点O为圆心,OB长为半径画弧,交射线BO于点D;
②连接AD,CD.
四边形ABCD是所求作的矩形.
根据小东设计的尺规作图过程,
(1)使用直尺和圆规,依作法补全图形(保留作图痕迹);
(2)完成下面的证明.
证明:∵点O为AC的中点,
∴AO=CO.
又∵BO= ,
∴四边形ABCD是平行四边形( )(填推理的依据).
∵∠ABC=90°,
∴□ABCD是矩形( )(填推理的依据).
已知:如图,在Rt△ABC中,∠ABC=90°,O为AC的中点.
![](https://img.xkw.com/dksih/QBM/2022/1/26/2903002187677696/2903548966772736/STEM/2e98e29ade694734ae2387c1d9122746.png?resizew=139)
求作:四边形ABCD,使得四边形ABCD是矩形.
作法:①作射线BO,以点O为圆心,OB长为半径画弧,交射线BO于点D;
②连接AD,CD.
四边形ABCD是所求作的矩形.
根据小东设计的尺规作图过程,
(1)使用直尺和圆规,依作法补全图形(保留作图痕迹);
(2)完成下面的证明.
证明:∵点O为AC的中点,
∴AO=CO.
又∵BO= ,
∴四边形ABCD是平行四边形( )(填推理的依据).
∵∠ABC=90°,
∴□ABCD是矩形( )(填推理的依据).
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【推荐1】已知△ABC是等边三角形,点D、F分别在边BC、AC上,且DF∥AB,过点A平行于BC的直线与DF的延长线交于点E,连接CE、BF.
![](https://img.xkw.com/dksih/QBM/2013/5/20/1573653834006528/1573653839953920/STEM/d15e73b9875b4e0781ffefe29fafd576.png?resizew=150)
(1)求证:△ABF≌△ACE;
(2)若D是BC的中点,判断△DCE的形状,并说明理由.
![](https://img.xkw.com/dksih/QBM/2013/5/20/1573653834006528/1573653839953920/STEM/d15e73b9875b4e0781ffefe29fafd576.png?resizew=150)
(1)求证:△ABF≌△ACE;
(2)若D是BC的中点,判断△DCE的形状,并说明理由.
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【推荐2】如图,
是
的直径,C,D是
上两点,C是
的中点,过点C作
的垂线,垂足为E,连接
交
于点F.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/5/af1f7c08-b815-4044-8d92-0b253a529888.png?resizew=171)
(1)求证:
是
的切线;
(2)若
,
,求
的半径.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bd6ffb78dad3375efa3b08ab518553d.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/d40b319212a7e7528b053e1c7097e966.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/5/af1f7c08-b815-4044-8d92-0b253a529888.png?resizew=171)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70abed7faf55deb24162255c5ad59577.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c8110f066b294763b30456f7cd90d1e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
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【推荐1】如图,在
中,点
是
边的中点,过点
作直线
,
的平分线和外角
的平分线分别交
于点
,
.
是矩形:
(2)若
,
,求四边形
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c1dc52a8ba9f389800eb92dbd145bf5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
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(2)若
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解答题-证明题
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适中
(0.65)
【推荐2】如图,在
ABCD中,AC⊥AB,AC与BD相交于点O,将△ABC沿对角线AC翻转180°,得到△AB'C.
(1)求证:以A,C,D,B' 为顶点的四边形是矩形;
(2)若四边形ABCD的面积为12平方厘米,求翻转后重叠部分的面积,即△ACE的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81a5328919a7cec382c2e91c9c528fc1.png)
(1)求证:以A,C,D,B' 为顶点的四边形是矩形;
(2)若四边形ABCD的面积为12平方厘米,求翻转后重叠部分的面积,即△ACE的面积.
![](https://img.xkw.com/dksih/QBM/2021/7/26/2772417932034048/2775164261408768/STEM/25c45a36-cf50-4e1d-9c75-3495d1561229.png)
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