点D是
的边
上一点,且
,点E是
的中点,若
,求
的长.
![](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/989674e0ed00ae757fa8a889bdd7449c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/070bc896d35495237fd65576e9b6f88e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/2021/10/3/2821612722561024/2821888918577152/STEM/5a6edbf5-8a5c-4341-a6be-f3e5683f8174.png?resizew=158)
更新时间:2021-10-04 07:30:36
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】【基础回顾】(1)如图1,
是正方形
中
边上任意一点,以点A为中心,将△ADE顺时针旋转90°后得到
,若连接
,则△AEE' 的形状为______;
![](https://img.xkw.com/dksih/QBM/2022/4/5/2951502527160320/2951638743089152/STEM/ae788b14-6ef8-473b-91c4-1b2836b68f1a.png?resizew=162)
【类比探究】(2)如图2,在(1)的条件下,设
与
相交于点
,在
上取点
,使
,连接
,猜想
与
的数量关系,并给予证明;
![](https://img.xkw.com/dksih/QBM/2022/4/5/2951502527160320/2951638743089152/STEM/f27c1bd9-ddb1-4e16-9557-b4f67219eb00.png?resizew=162)
【联想拓展】(3)如图3,在△ABC中,
,
.点
在
上,求
,
,
之间存在的数量关系.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1201f9efbe51c5d9eba973d9f9831159.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/827be85b8f921007a5cf9edb64bd3491.png)
![](https://img.xkw.com/dksih/QBM/2022/4/5/2951502527160320/2951638743089152/STEM/ae788b14-6ef8-473b-91c4-1b2836b68f1a.png?resizew=162)
【类比探究】(2)如图2,在(1)的条件下,设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/827be85b8f921007a5cf9edb64bd3491.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fcb7f5ef0f13d468ff6c4660e5921e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf3d566704b44ea4ef1f99c37bd46902.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf3d566704b44ea4ef1f99c37bd46902.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bb512f8aad26a4d219b91d585a4b960.png)
![](https://img.xkw.com/dksih/QBM/2022/4/5/2951502527160320/2951638743089152/STEM/f27c1bd9-ddb1-4e16-9557-b4f67219eb00.png?resizew=162)
【联想拓展】(3)如图3,在△ABC中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://img.xkw.com/dksih/QBM/2022/4/5/2951502527160320/2951638743089152/STEM/4ad1f13d-e973-4c5f-9bd5-1f391fc1539f.png?resizew=216)
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解答题-问答题
|
适中
(0.65)
【推荐2】定义:我们把对角线相等的凸四边形叫做“等对角线四边形”.
(2)问题探究:如图1,在四边形
中,
,
的中垂线恰好交于
边上一点P,连结
,请判断四边形
是不是等对角线四边形,并说明理由.
(3)如图2,已知在
中,
,D为线段
的垂直平分线上一点,若以点A,B,C,D为顶点的四边形是等对角线四边形,求这个等对角线四边形的面积.
(2)问题探究:如图1,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45fecabc1d9e36cb8697d5275656106d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ba48366317ebea1c9dd5e4e67e03092.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d578394cd8e4d7a705599269c512960.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(3)如图2,已知在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5a9d0aaecd32f550708599acf5bd638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
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解答题-证明题
|
适中
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【推荐1】如图,
为等边三角形,点D是延长线上一点,且
,
的垂直平分线交
于
,过
作
交
于
.
为等边三角形;
(2)若
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/caedb55e1410c5083c2a8645008527a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee73452ee4d5437f1399f1235b95e55f.png)
![](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/4c105d6ba18fbb0581fb982175e2eac9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae1fbb1f69f91e628aa45e6265edca4e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fcda8436a5e68816b74177e6d51cba7.png)
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解答题-作图题
|
适中
(0.65)
名校
【推荐2】数学上的对称通常是指轴对称、中心对称,以及对称的思想方法.某数学兴趣小组进行折纸活动,来感受图形中的对称思想.如图1,将正方形纸片
对折后展开,得到折痕
;如图2,将纸片再次折叠,使点
落在折痕
上,记作点
;如图3,连接
,得到
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/16/72012784-eabf-48dd-a9ef-b2c902de7da6.png?resizew=426)
(1)请判断:
是 三角形;
【问题提出】
兴趣小组成员想要进一步找到正方形中最大的等边三角形.
【问题探究】
如图4,小颖认为正方形中最大等边三角形的顶点一定落在正方形的边上,她将图4的
沿
进行平移,使点
与点
重合(如图5),再将
绕点
旋转,使
与对角线
垂直,延长
分别交
于点
和
(如图6),连接
,便可得到如图7的最大等边三角形
.设正方形
的边长为
.
(2)小丽利用对称的思想,即
关于直线
对称,从而求得
,则
.(
,
,
)
(3)若不知道
角的三角函数值,请你换一种方法求
的长.
【问题解决】
(4)如图8,已知正六边形中最大的等边三角形边长为
,则该正六边形的边长为 .
【拓广应用】
(5)
纸的长为
,宽为
,现要在
纸中剪一个最大等边三角形.请你在图9中画出示意图(不需尺规作图),并求该最大等边三角形的边长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b39addc1173a458af87ed5c5e3f06466.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b39addc1173a458af87ed5c5e3f06466.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/004104bafb5f30338123d4ea2b7fedde.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/16/72012784-eabf-48dd-a9ef-b2c902de7da6.png?resizew=426)
(1)请判断:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/004104bafb5f30338123d4ea2b7fedde.png)
【问题提出】
兴趣小组成员想要进一步找到正方形中最大的等边三角形.
【问题探究】
如图4,小颖认为正方形中最大等边三角形的顶点一定落在正方形的边上,她将图4的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43607ec47fdeeb115481099cd47aa8f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/244acdf0f984332117987dbe2627da25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/902f97913e1af1e6c793f7edfe6b2114.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02008039afa09dabf178facaed0eb4f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90227acf6ca686cd1dbd1dd556f1eb10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87c0bfeadcf17b2a45896071f07a4a5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
(2)小丽利用对称的思想,即
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f2ea13010e2399194be2a681310543e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46429cb75526caf8aa0f0bcc64464482.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f79997547fb75e88ad1e2c66989a4a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b7bb1dd9e1bb49e95ecc1eb09b17f37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff421393cf5973dbed11a21ad22926cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a79839efc99852a6d35901e51fb4cd8d.png)
(3)若不知道
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76c12e76fbd84eeec721386bd3b04cc4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
【问题解决】
(4)如图8,已知正六边形中最大的等边三角形边长为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
【拓广应用】
(5)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e47cd514b2920609e3781c87df6ab70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df5cb5fb729b919d931f1a0b484064e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3f87f10417a0042564218a74f5a3871.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e47cd514b2920609e3781c87df6ab70.png)
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解答题-作图题
|
适中
(0.65)
【推荐1】如图,在
的正方形网格中,每个小正方形的边长为1,已知点A在格点上,请在所给的网格中按下列要求画出图形.
(1)在图1中,画一条长为
的线段
,且点C在格点上;(只需画出一条符合条件的线段)
(2)在图2中,画一个顶点都在格点上的平行四边形
,使其中一条对角线长为
,且面积为6.(只需画出一个符合条件的图形)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/954253b16a82489bb0e152543428c68a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/17/831716b5-f509-4176-aa24-cd5609017b96.png?resizew=474)
(1)在图1中,画一条长为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4056761b8f826eeb6ad8c9a151d3c9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
(2)在图2中,画一个顶点都在格点上的平行四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4056761b8f826eeb6ad8c9a151d3c9c.png)
您最近一年使用:0次
解答题-证明题
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适中
(0.65)
【推荐2】如图,
的直径
,
为
延长线上一点,
与
相切于点
,过点
作弦
,连接
.
为
的中点;
(2)若
,求四边形
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cee49e97546d466ba3ee630e08cdc3c.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/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc682dd2e077dde34ab9d9e4434a4805.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bd6ffb78dad3375efa3b08ab518553d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1beff025b32f688316009552d2fd8e1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4532089d5b232b1b8efc4e3e72cd782c.png)
您最近一年使用:0次