如图,平行四边形ABCD中,点E为BC中点,AD=2AB,连接AE、DE,F、H分别为AE、DE的中点.
(1)求证:CF与EH互相平分;
(2)若AB=25,DE=40,求CF的长.
(1)求证:CF与EH互相平分;
(2)若AB=25,DE=40,求CF的长.
![](https://img.xkw.com/dksih/QBM/2021/12/10/2869694731763712/2874205893140480/STEM/37a939c9ca224007b45d1a98b1e4d615.png?resizew=199)
20-21八年级上·广东深圳·期中 查看更多[2]
(已下线)广东省深圳市深圳中学初中部竞赛班(3+2体系)2020-2021学年八年级上学期期中数学试题2(已下线)广东省深圳市深圳中学初中部竞赛班(3+2体系)2020-2021学年八年级上学期期中数学试题1
更新时间:2021-12-17 05:29:46
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在Rt△ABC中,∠ACB=90°,D为AB中点,
.
(1)试判断四边形BDCE的形状,并证明你的结论;
(2)若∠ABC=30°,AB=4,则四边形BDCE的面积为 .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/963a9877fb5483e9f1a8c9dc4f86d753.png)
(1)试判断四边形BDCE的形状,并证明你的结论;
(2)若∠ABC=30°,AB=4,则四边形BDCE的面积为 .
![](https://img.xkw.com/dksih/QBM/2022/1/4/2887034775797760/2889210298933248/STEM/6badabb06d7f4c3186e3eff24d4d86d1.png?resizew=205)
您最近一年使用:0次
解答题-作图题
|
适中
(0.65)
【推荐2】(1)如图1,已知△ABC是等边三角形,D,E分别为边AB,AC的中点,连接BE,CD,BE与CD交于点P.试判断:①∠BPD的度数为______;②线段PB,PD,PE之间的数量关系:PB______PD+PE.(填写“>”或“<”或“=”)
![](https://img.xkw.com/dksih/QBM/2022/4/28/2967915045912576/2972907047510016/STEM/db033a91-84b4-4fb7-8620-062d57fa9cbf.png?resizew=478)
(2)若点E是边AC所在射线AC上一动点(
).
按下列步骤画图:
(ⅰ)连接BE,作点A关于BE所在直线的对称点D,连接BD;
(ⅱ)作射线DC,交BE所在直线于点P.
小明所做的图形如图2所示,他猜想:
.下面是小明的思考过程:
如图2,延长PD到F,使得
,连接BF.发现
,从而得到
,又因为
所以可得
,进而得到
为等边三角形,从而得到线段PB,PC,PD之间关系是
.
小华同学画图时,把点E标在了边AC的延长线上,请就图3按要求画出图形,猜想线段PB,PC,PD之间的数量关系,并说明理由.
(3)如图4,在
中,若
,
,点E是射线AC上一动点(
),连接BE,作点A关于直线BE的对称点D,连接DC,射线DC与射线BE交于点P,若
,
,请直接用m,n表示PD的长.
![](https://img.xkw.com/dksih/QBM/2022/4/28/2967915045912576/2972907047510016/STEM/db033a91-84b4-4fb7-8620-062d57fa9cbf.png?resizew=478)
(2)若点E是边AC所在射线AC上一动点(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efa6dfc6d785c1699661e915d12c6762.png)
按下列步骤画图:
(ⅰ)连接BE,作点A关于BE所在直线的对称点D,连接BD;
(ⅱ)作射线DC,交BE所在直线于点P.
小明所做的图形如图2所示,他猜想:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b279193845b2380258ba4b60f0afbe6.png)
如图2,延长PD到F,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1b3d0922017aafaefa9491ce8d10f5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e90d180b4fc1355ca395049c815fd65f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52e450abeb97e7848ef35fcee286b27e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13fcbf57225326452fbe833f2b577697.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/150fe3137f76a6f05d9148c7d8c1810e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b279193845b2380258ba4b60f0afbe6.png)
小华同学画图时,把点E标在了边AC的延长线上,请就图3按要求画出图形,猜想线段PB,PC,PD之间的数量关系,并说明理由.
(3)如图4,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3570a95f68349fcd9417fcda62e78e7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efa6dfc6d785c1699661e915d12c6762.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/554645462113f7c8e22f7ac28887f5c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e119ea75c9045f4fdbb55af3ef86b69c.png)
![](https://img.xkw.com/dksih/QBM/2022/4/28/2967915045912576/2972907047510016/STEM/af5c9832-8e5b-4146-9ed9-0499068e523e.png?resizew=215)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐1】在
中,点D、E、F分别在
、
、
上,且
,
,
,求证:
.
![](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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6370d6c626bdabf1fc694501ee6c714f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd4d556e9b78b8b4be157b2b3926d15e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3970e4cd14e18b5eeff2a47b71d5181.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fedf634c305704c1c13cb0353d5dc7c5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/22/b66e0081-9b2a-4339-b109-a9362db17e52.png?resizew=193)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图,已知在四边形ABCD中,BC=AD,点E和F分别是BC和AD边上的中点,且AE=CF,求证:AB∥CD.
![](https://img.xkw.com/dksih/QBM/2020/8/19/2530958164975616/2531219773456384/STEM/65d1a4649bc747b6b097ac1d9c19de50.png?resizew=261)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】已知△ABC,延长BC到D,使CD=BC.取AB的中点F,连接FD交AC于点E.
![](https://img.xkw.com/dksih/QBM/2015/12/28/1573946073473024/1573946079272960/STEM/7625f1da-2382-4b18-811f-84dbb8b4a3d7.png?resizew=208)
(1)求AE:AC的值;
(2)若AB=a,FB=EC,求AC的长.
![](https://img.xkw.com/dksih/QBM/2015/12/28/1573946073473024/1573946079272960/STEM/7625f1da-2382-4b18-811f-84dbb8b4a3d7.png?resizew=208)
(1)求AE:AC的值;
(2)若AB=a,FB=EC,求AC的长.
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图1,在△ABC中,
,点DE、分别在边AB、AC上,
,连接DC,点P、Q、M分别为DE、BC、DC的中点,连接MQ、PM.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/10/3daf9738-9b25-4a34-9edb-df1545b30851.png?resizew=351)
(1)求证:
;
(2)当
时,求PMQ的度数;
(3)将△ADE绕点A沿逆时针方向旋转到图2的位置,若
,判断△ADE的形状,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d212c1709b8e72a055cf1b5381ef64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/10/3daf9738-9b25-4a34-9edb-df1545b30851.png?resizew=351)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66a958140160f2125d3e20b225752d40.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d777d15cd733338ecfd0ea63819f62c.png)
(3)将△ADE绕点A沿逆时针方向旋转到图2的位置,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f959709747004dcf4e9c84ad544dc65c.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,正方形ABCD中,E是对角线BD上一点,连接AE,过点E作
,交边BC于点F.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/23/0a06bba1-7b1e-4e59-b8de-8784137208f9.png?resizew=333)
(1)求证:EA=EF:
(2)写出线段FC,DE的数量关系并加以证明;
(3)若AB=4,FE=FC,求DE的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/992a19339adac3a2f1aab1fbc11b1c68.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/23/0a06bba1-7b1e-4e59-b8de-8784137208f9.png?resizew=333)
(1)求证:EA=EF:
(2)写出线段FC,DE的数量关系并加以证明;
(3)若AB=4,FE=FC,求DE的长.
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】“五一”节期间,许多露营爱好者在我市郊区露营,为遮阳和防雨会搭建一种“天幕”,其截面示意图是轴对称图形,如图,对称轴垂直于地面的支杆
所在直线,用绳子拉直
后系在树干
上的点E处,使得点A、D、E在一条直线上,通过调节点E的高度可控制“天幕”的开合,
.
(参考数据:
,
)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/26/a1533156-c7ec-48e7-8380-80634acfd9d8.png?resizew=139)
(1)天晴时打开“天幕”,若
,求遮阳宽度
(结果精确到0.1m);
(2)下雨时收拢“天幕”,
从
减少到
,求点E下降的高度.(结果精确到0.1m).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52d77f82c2ccbf21a8130b316dee05e5.png)
(参考数据:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8eb41048518990b496a426e2ae5673ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c894b7d6baa55c80c64e74748dad898.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/26/a1533156-c7ec-48e7-8380-80634acfd9d8.png?resizew=139)
(1)天晴时打开“天幕”,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ecc4fb2be3e82e633a88cb52eeee879.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(2)下雨时收拢“天幕”,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/225803a7818b0985a1b96d8e0a627251.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79a97bb4dcfab4ec7539bc783d563c49.png)
您最近一年使用:0次