如图,已知
和
均为等腰三角形,
,
.
(1)问题发现:如图①,当
时,点B、D、E在同一直线上,连接CE,请判断线段BD、CE之间的数量关系及
的度数,并说明理由:
(2)拓展探究:如图②,当
时,点B、D、E在同一直线上,连接CE,请判断线段BD、CE之间的数量关系及
的度数,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c056a26c993ab806c603f063f78da923.png)
(1)问题发现:如图①,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df1a6bc483edf9e65f6f7391493ddd7a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/936f5f26aac7197d42a41081fb1fda0e.png)
(2)拓展探究:如图②,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd9776aa108071b50b71adf181bbdaf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/936f5f26aac7197d42a41081fb1fda0e.png)
![](https://img.xkw.com/dksih/QBM/2021/11/9/2847502213890048/2850213074132992/STEM/aeb631ec-d1db-4046-aaf9-3486d66d669d.png)
21-22九年级上·广西北海·期中 查看更多[2]
更新时间:2021-11-13 07:56:15
|
相似题推荐
解答题-证明题
|
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(0.85)
【推荐2】如图所示,
在同一直线上,
,
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/7/0b4fd960-0718-4cf8-b75c-ac86fb674dfb.png?resizew=140)
(1)求证:
.
(2)求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05d834229bc2c93f14cd5eb1a4d2ba32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ac85be72fc51ef4c90de7e00c5556cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2151388a129f019c64301dfbee190c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e932b4add3175358f15be0e1f7104e79.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/7/0b4fd960-0718-4cf8-b75c-ac86fb674dfb.png?resizew=140)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63040735d25a24ede5a4b3203b1b2165.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdd721393a3d94cd3560678a50731792.png)
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【推荐1】如图所示,AB是⊙O的直径,P为AB延长线上任意一点,C为半圆
的中点,PD切⊙O于点D,连CD交AB于点E,求证:PD=PE.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16d65cecaf8a3dc2953f4109c75a981e.png)
![](https://img.xkw.com/dksih/QBM/2021/11/27/2860155331911680/2864538900373504/STEM/c814a18a-d331-4144-a126-6fc784d35d63.png?resizew=219)
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解答题-作图题
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名校
【推荐2】下面是小明同学设计的“作一个角等于已知角的2倍”的方法:
已知:如图,∠AOB.
求作:∠ADC,使∠ADC=2∠AOB,且点D在射线OA上.
作法:如图,
①在射线OB上任取一点C;
②分别以O、C为圆心,大于
的长为半径画弧,两弧在OB两侧分别交于点M、N两点;
③作直线MN,交OA于点D,连接DC,则∠ADC为符合题意的角.
![](https://img.xkw.com/dksih/QBM/2022/6/5/2994603864858624/2995332771323904/STEM/b3aa112c866147b7a9222a4262956fe9.png?resizew=156)
(1)根据小明同学设计的尺规作图过程,完成以下证明过程:
证明:∵OM=CM,ON=CN,
∴MN是线段OC的垂直平分线,
∴OD=______,
∴∠AOB=______,
∵∠ADC=∠AOB+∠DCO,
∴∠ADC=2∠AOB.
(2)以上作图过程中没有用到的理论依据是______(填序号)
①线段垂直平分线上的点到线段两个端点的距离相等;
②三角形的任意两边之和大于第三边;
③三角形的外角等于与它不相邻的两内角之和;
④等腰三角形的底角相等.
已知:如图,∠AOB.
求作:∠ADC,使∠ADC=2∠AOB,且点D在射线OA上.
作法:如图,
①在射线OB上任取一点C;
②分别以O、C为圆心,大于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3e4818b793ca69be2b85918ab05e9fb.png)
③作直线MN,交OA于点D,连接DC,则∠ADC为符合题意的角.
![](https://img.xkw.com/dksih/QBM/2022/6/5/2994603864858624/2995332771323904/STEM/b3aa112c866147b7a9222a4262956fe9.png?resizew=156)
(1)根据小明同学设计的尺规作图过程,完成以下证明过程:
证明:∵OM=CM,ON=CN,
∴MN是线段OC的垂直平分线,
∴OD=______,
∴∠AOB=______,
∵∠ADC=∠AOB+∠DCO,
∴∠ADC=2∠AOB.
(2)以上作图过程中没有用到的理论依据是______(填序号)
①线段垂直平分线上的点到线段两个端点的距离相等;
②三角形的任意两边之和大于第三边;
③三角形的外角等于与它不相邻的两内角之和;
④等腰三角形的底角相等.
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【推荐1】在
中,
,若M是BC边上任意一点,将
绕点A逆时针旋转得到
,点M的对应点为点N,连接MN.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/31/ccb3e2cb-6ac7-4703-9546-b86e14c01bb8.png?resizew=395)
(1)如图①,当
时,求
的大小;
(2)如图②,当
时,求
的大小;
(3)如图③,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a5e0a51c9e14fb246b0ba0b231c1e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db609c0ddcb9af21ddbf443d3e527cfa.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/31/ccb3e2cb-6ac7-4703-9546-b86e14c01bb8.png?resizew=395)
(1)如图①,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41bef89ac0dd5ae192cd9c7222d5041b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/358c69b4f6c350c35d19d33c69f2a2a8.png)
(2)如图②,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/929c999284741732e7b1138d0d383737.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
(3)如图③,求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8068934f744ed750cb6962fea0c10072.png)
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【推荐2】如图,在四边形
中,
,
为对角线,
平分
,交
于点
,连接
,若
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c2413a5658da02710d389e2f559e306.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](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/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e918b70b02a73685e3c536c7f380e2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3c7001d07f8facdcefdcd9a4bf2eadf.png)
![](https://img.xkw.com/dksih/QBM/2023/1/31/3164553625550848/3164806907805696/STEM/c43eb616fab24cd5b06deea6d2b36046.png?resizew=279)
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解答题-问答题
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【推荐1】如图,河对岸有一路灯杆
,在灯光下,小明在点D处测得自己的影长
,沿
方向到达点F处再测得自己的影长
.如果小明的身高为
,求路灯杆
的高度.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6eade0ef475eea0bdb531179a2a47c51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c41f1f42f868971aa89e441501f01c5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8faf2eb744734804c85b22f408ee043a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/7/dc8d66f2-ee59-4a27-8864-325f70b714a6.png?resizew=151)
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解答题-证明题
|
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【推荐2】如图,在平行四边形
中,
为
上一点,连接
,F为
上一点,且
.
(1)求证:
.
(2)若
,
,
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a6c6e7c025362c46a64a8956761f08e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a6c6e7c025362c46a64a8956761f08e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccef98ccb1ce7de9339a879783dd7628.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/10/950f348c-3bb9-4498-86c2-ddf58675acc7.png?resizew=194)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbfdb24237407e20ca35a4d269b62fe1.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8feb9fdc5582ad3e9853890ac2738d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76d527d4795ece4a5756d1cf8dba31e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/720db935aac742c0dc6d7e48fa1bc38c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79ff575e55857af133edb24c8e61504f.png)
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