如图,在边长为2的等边
中,以点O为圆心画弧,与
边相切于点C,交
于点D,交
于点E,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fe95f656b98b53f71a9d72bf0c9a4b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0c44512cb86bcf48c6d21357f45b533.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/5/88203cdf-979f-45f0-815c-4702b8705141.png?resizew=150)
更新时间:2022-11-04 16:24:02
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相似题推荐
解答题-问答题
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【推荐1】如图,在等边三角形
中,
的平分线与
的平分线相交于
,过点
作
交
于点
,交
于点
,
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/613dedf2d90e58591b7ac4a250ac7b5d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/15/249d5ef8-b6da-413e-9830-1f9cb637d9d0.png?resizew=174)
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【推荐2】如图,
是等边三角形,曲线
叫做“等边三角形的渐开线”,曲线的各部分均为圆弧.设
的边长为
厘米,求前
段弧长的和(即曲线
的长)是多少厘米?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a24633bfac244695367995cdb31844d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acfb72b3acab422370a950ce4f14cae4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/175f7c51-cbc5-4c32-9573-e1e8033f804d.png?resizew=178)
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解答题-作图题
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真题
【推荐1】我们学习过利用用尺规作图平分一个任意角,而“利用尺规作图三等分一个任意角”曾是数学史上一大难题,之后被数学家证明是不可能完成的,人们根据实际需要,发明了一种简易操作工具--------三分角器.图1是它的示意图,其中
与半圆
的直径
在同一直线 上,且
的长度与半圆的半径相等;
与
重直于点
足够长.
使用方法如图2所示,若要把
三等分,只需适当放置三分角器,使
经过
的顶点
,点
落在边
上,半圆
与另一边
恰好相切,切点为
,则
就把
三等分了.
为了说明这一方法的正确性,需要对其进行证明.如下给出了不完整的“已知”和“求证”,请补充完整,并写出“证明”过程.
![](https://img.xkw.com/dksih/QBM/2020/7/16/2507276540919808/2507740623151104/STEM/28d35773-c572-41fc-9053-e56c95dfbe16.png)
已知:如图2,点在
同一直线上,
垂足为点
,
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/529c8336c1a523cccbdda7cf183cf219.png)
使用方法如图2所示,若要把
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/435f30095577dc714634354f5ad27715.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/435f30095577dc714634354f5ad27715.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b46c607b3deac746c0ef3389ad8f65c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c4c865445dda4a59b6d5cb18fd74404.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04122fc1074cff7e73beea9c2ec76ca2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/435f30095577dc714634354f5ad27715.png)
为了说明这一方法的正确性,需要对其进行证明.如下给出了不完整的“已知”和“求证”,请补充完整,并写出“证明”过程.
![](https://img.xkw.com/dksih/QBM/2020/7/16/2507276540919808/2507740623151104/STEM/28d35773-c572-41fc-9053-e56c95dfbe16.png)
已知:如图2,点在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c7d41f6e9ebcd509b0c3446029d9ac2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2a5d70fd8b5e381375ea6d4b45e4d9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
求证:
![](https://img.xkw.com/dksih/QBM/2020/7/16/2507276540919808/2507740623151104/STEM/c48aba70-da47-4be0-bf9d-aecfff3ee39b.png)
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【推荐2】如图,
为
的直径,点C在
上,
与过点C的切线互相垂直,垂足为D.连接
并延长,交
的延长线于点E.求证:
.
![](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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be5fc6ead6416492c231c320a5486f86.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/18/e6736d1c-0ee6-44b5-82b9-39cd4d802e59.png?resizew=134)
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解答题-作图题
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【推荐1】如图,正方形网格中,每个小正方形的边长都是一个单位长度,在平面直角坐标系内, △ABO的三个顶点坐标分别为A(-1,3),B(-4,3),O(0,0).
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/7/5197b4c6-e216-4dbb-8f78-0ccbbd94c373.png?resizew=262)
(1)画出△ABO绕点O顺时针旋转90°后得到的△A1B1O;
(2)在(1)的条件下,求点A旋转到点A1所经过的路径长(结果保留π).
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/7/5197b4c6-e216-4dbb-8f78-0ccbbd94c373.png?resizew=262)
(1)画出△ABO绕点O顺时针旋转90°后得到的△A1B1O;
(2)在(1)的条件下,求点A旋转到点A1所经过的路径长(结果保留π).
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【推荐2】如图,有一直径是
的圆形铁皮,现从中剪出一个圆周角是90°的最大扇形ABC.
![](https://img.xkw.com/dksih/QBM/2022/1/16/2895572451368960/2952465850204160/STEM/c2082e6e-bef3-4e30-b06e-213bad90cabb.png?resizew=149)
(1)求AB的长;
(2)用该扇形铁皮围成一个圆锥,求所得圆锥的底面圆的半径.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://img.xkw.com/dksih/QBM/2022/1/16/2895572451368960/2952465850204160/STEM/c2082e6e-bef3-4e30-b06e-213bad90cabb.png?resizew=149)
(1)求AB的长;
(2)用该扇形铁皮围成一个圆锥,求所得圆锥的底面圆的半径.
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