如图所示,在梯形ABCD中,AD∥BC,∠BDC=90°,E为DC上一点,∠BDE=∠DBC.
![](https://img.xkw.com/dksih/QBM/2014/2/26/1573709931839488/1573709937426432/STEM/85e2fa86e3e24557ad4c39f73a7f6dea.png)
(1)求证:DE=CE;
(2)若
,试判断四边形ABED的形状,并说明理由.
![](https://img.xkw.com/dksih/QBM/2014/2/26/1573709931839488/1573709937426432/STEM/85e2fa86e3e24557ad4c39f73a7f6dea.png)
(1)求证:DE=CE;
(2)若
![](https://img.xkw.com/dksih/QBM/2014/2/26/1573709931839488/1573709937426432/STEM/6974a27532ca470ab5baf1ff70588451.png)
更新时间:2016-12-05 19:43:58
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相似题推荐
解答题-证明题
|
适中
(0.65)
真题
【推荐1】如图,
是
的直径,点E,C在
上,点C是
的中点,
垂直于过C点的直线
,垂足为D,
的延长线交直线
于点F.
是
的切线;
(2)若
,
,①求
的半径;②求线段
的长.
![](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/1b19c646bcb6160197fdf12a9cb31a0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30b0393ce62b24aa5f9b740d4cc6743b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89fe5fde2c81bedb8fc6142a068f8fb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
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名校
【推荐2】已知:在
中,点
在直线
上,点
在同一条直线上,且
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f35a71a3c487ab900b8d142fd7bb1bd9.png)
(1)如图1,若
平分
,求证:
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/fe28edb8-d0f4-4bc4-a712-a3b123909adf.png?resizew=150)
(2)如图2,若
平分
的外角
,交
的延长线于点
,问:
和
的数量关系发生改变了吗?若改变,请写出正确的结论,并证明;若不改变,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3c65edad25ddd666cdce0d7e5afefc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2fb188915d2e3d7bfd633fa18221b07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc7372745342e507f47de35243c451b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f35a71a3c487ab900b8d142fd7bb1bd9.png)
(1)如图1,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/caaa9844fb467ea2cb2103bf91e001f6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/fe28edb8-d0f4-4bc4-a712-a3b123909adf.png?resizew=150)
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3c65edad25ddd666cdce0d7e5afefc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d786ee723231d4ca87eb9d011a378b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a55a1a244f81097e05e715b69580faa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db866ecc0c098bfc32ec8a43b65bdd58.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/46c92955-beb6-4c12-acea-66a8b491f11e.png?resizew=187)
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【推荐1】数学上,把一组对边平行,另一组对边不平行的四边形叫做梯形.平行的一组对边叫做梯形的底,短的称为上底,长的称为下底;另一组不平行的对边叫做梯形的腰.连接两腰中点的线段叫做梯形的中位线.如图(1),在梯形
中,
,
、
分别为两腰
和
的中点,连接
,则
为梯形
的中位线.
![](https://img.xkw.com/dksih/QBM/2021/8/13/2785069095108608/2802752577077248/STEM/926abefb-80c6-48bc-b6cd-0feb8b02826c.png)
(1)经观察和测量你能发现
和两底
、
的关系是________;
(2)请用你所学过的知识证明你的结论.
(3)利用你所发现的结论解决问题:已知如图(2),直线n为平行四边形
外的任意一条直线,过
、
、
、
分别作垂线段
、
、
和
,则线段
、
、
和
的数量关系是________.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/2021/8/13/2785069095108608/2802752577077248/STEM/926abefb-80c6-48bc-b6cd-0feb8b02826c.png)
(1)经观察和测量你能发现
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
(2)请用你所学过的知识证明你的结论.
(3)利用你所发现的结论解决问题:已知如图(2),直线n为平行四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
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(0.65)
【推荐2】如图,已知梯形
,
,
,
.
的度数;
(2)过点D作
,垂足为点E,连接
,如果
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43493f72b8344f58143e9f445ec7d433.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/615fc8790237a1b09af51d6bcad6b595.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
(2)过点D作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68fbbd17c89f03dbb61cd6ffdb9a0344.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82773737609e65dea3c5c67099f1b10d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
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解答题-证明题
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【推荐1】如图,
中,
,
是斜边
上的中线,点E是
的中点,过点C作
交
的延长线于点F,连接
.
;
(2)①当线段
、
满足什么数量关系时,四边形
是正方形,并说明理由;
②已知
,
,求四边形
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ed8f7d3d7043d4b1eb98fc5c4e2fcd3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.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/b00a5239269d72d6f9632e7d77347106.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aebb5baea4ac1668b674a8634e15bcbc.png)
(2)①当线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d54f59859698f3cfdfe285b3cdb95125.png)
②已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/025df2a9934b457cf20d91604e430612.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c6e367d33bec31ce6035dbd46f9dfda.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d54f59859698f3cfdfe285b3cdb95125.png)
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【推荐2】如图,在△ABC 中,以AB为直径的⊙O分别交AC,BC于点 D,E.连接ED,若ED=EC.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/2/95b05194-95ff-425b-8462-baecbcd08274.png?resizew=152)
(1)求证:AB=AC;
(2)填空:①若∠C=60°,CD=4,则AB= ;
②连接OD,当∠A的度数为 时,四边形ODEB是菱形.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/2/95b05194-95ff-425b-8462-baecbcd08274.png?resizew=152)
(1)求证:AB=AC;
(2)填空:①若∠C=60°,CD=4,则AB= ;
②连接OD,当∠A的度数为 时,四边形ODEB是菱形.
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