如图,△ABC中,∠C=90º,AD是角平分线,CD=15,BD=25.求AC的长.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/14/11603b09-0910-49a7-93dd-e21d29784554.png?resizew=200)
18-19八年级下·全国·单元测试 查看更多[10]
北师大版 八年级数学下册 第一章 三角形的证明 单元检测卷人教版八年级下册 第十七章 勾股定理 章节测试【区级联考】安徽省合肥市包河区2018-2019学年八年级下学期期中考试数学试题天津市海河中学2018-2019学年八年级下学期3月月考数学试题甘肃省定西市临洮县2019-2020学年八年级下学期线上教学质量检测数学试题广西防城港市2019-2020学年八年级下学期期中数学试题广西防城港市上思县2019-2020学年八年级下学期期中数学试题广西壮族自治区崇左市宁明县2020-2021学年八年级下学期期中数学试题福建省龙岩市初级中学北城分校2020-2021学年八年级下学期第一次月考数学试题江苏省泰州市海陵区第二中学附属初中2023-2024学年八年级上学期12月月考数学试题
更新时间:2020-06-27 15:22:10
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解答题-证明题
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适中
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【推荐1】已知,如图,在
中,
,
,点E是线段AD上一点,且
.
(1)若
,求
的度数;
(2)判断直线BE与AC的位置关系并证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5f215a42c4b7078d8d65923eb9980e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3620030e8808da46df97330103827913.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7595bdaea3dfa548c0fcfe3708387476.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a76ffd241623ec4ee9fd08876464def3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cfc2771aa0d5b97d2297f8a26a6f6b1.png)
(2)判断直线BE与AC的位置关系并证明.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/25/1862262b-d9e9-47b5-9638-f4f1c0c30353.png?resizew=202)
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解答题-证明题
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适中
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【推荐2】综合与实践
问题情境:
在数学课上,老师让同学们利用长方形纸片
进行折叠研究数学问题:如图1,点P是长方形
的边
上一动点,连接
,将
沿着
折叠得到
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/27/3df1e8c7-203f-40e1-b435-b5473cec9fd3.png?resizew=163)
初步探究:
(1)如图1,当点P与点A重合时,
与
交于点E,求证:
;
深入探究:
(2)如图2,当点P为
的中点时,延长
交
于点F,连接
,求证:
;
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/27/e80b4d85-acbe-4156-8c19-a86f7614aca3.png?resizew=144)
拓展延伸:
(3)在问题(2)中,若
,
,
的面积为
,直接写出长方形
的面积.
问题情境:
在数学课上,老师让同学们利用长方形纸片
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/357265c532428e886a643e8e653eec9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/308fb22e644ec66de2ba4fe466fc8393.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/27/3df1e8c7-203f-40e1-b435-b5473cec9fd3.png?resizew=163)
初步探究:
(1)如图1,当点P与点A重合时,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/143e346ac3950f60077291dda2be73c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d652d658b8416353ccbb91f752e78060.png)
深入探究:
(2)如图2,当点P为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ffb952f86442845da723fd291564484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fb26d84907c923278ac4626a9d58947.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2482a7330dbb1e858c6be7ea990b083c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/27/e80b4d85-acbe-4156-8c19-a86f7614aca3.png?resizew=144)
拓展延伸:
(3)在问题(2)中,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebc55a709c664b978f99360a77d2b041.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/169145cfb31e4fc502a3b2f47a644831.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0936e532862712045365cb3f63fced9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7c46e0b0475de3144ef5b773c451f4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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解答题-作图题
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名校
【推荐1】如图,
中,
.
(1)用尺规作图法在
上找一点D.使得点D到边
的距离相等(保留作图痕迹,不用写作法);
(2)在(1)的条件下,若
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/17/df66deff-6364-42aa-8b16-ea8058cb3246.png?resizew=188)
(1)用尺规作图法在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86cae7cc6665dc8edfb9060075b3afb9.png)
(2)在(1)的条件下,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa850b620d4a57e082a877cc764369ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
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解答题-证明题
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适中
(0.65)
名校
【推荐2】如图,
中,点D在
边上,
,
的平分线交
于点E,过点E作
,垂足为
,且
,连接
.
平分
;
(2)若
,求
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec6770d3bec16ffbbfb49f4df24c2171.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab00e0cff0876c4183a47f1272cf9928.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db22fd88641ac3c3d75573fd8d715271.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/3981e7286d41960daf4e110c1c84e03a.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62d62ca3f6573d3bcf3063cd36c1a566.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
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解答题-问答题
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适中
(0.65)
【推荐1】如图,在直角坐标系中,Rt△AOB的两条直角边OA,OB分别在x轴的负半轴,y轴的负半轴上,且OA=2,OB=1.将Rt△AOB绕点O按顺时针方向旋转90°,再把所得的像沿x轴正方向平移1个单位,得△CDO.
![](https://img.xkw.com/dksih/QBM/2015/3/13/1573811184492544/1573811190226944/STEM/86759a560ca84721837be2c94cd16dff.png)
(1)写出点A,B,C,D的坐标;
(2)求点A和点C之间的距离.
![](https://img.xkw.com/dksih/QBM/2015/3/13/1573811184492544/1573811190226944/STEM/86759a560ca84721837be2c94cd16dff.png)
(1)写出点A,B,C,D的坐标;
(2)求点A和点C之间的距离.
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解答题-问答题
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适中
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【推荐2】如图,是一个隧道的横截面,它的形状是以点O为圆心的圆的一部分.
经过圆心O,并且
于E,若
米,
米.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/7/9eff6b93-1693-480e-903f-dd2f22a17b58.png?resizew=135)
(1)
_____米.
(2)求
的半径.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b46c607b3deac746c0ef3389ad8f65c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/853d1df7f588ed855cfb0175561ae94d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e673ef2d48215ca84a48377f17d6df00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13f67c3ced4132d26bba732cd20cc211.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/7/9eff6b93-1693-480e-903f-dd2f22a17b58.png?resizew=135)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5277fa450a0c513a86a74420f8ee99f6.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
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