如图,在平行四边形ABCD中,∠A=45°,CD=12cm,点E在边AD上,EF与CD所在直线垂直,垂足为点F,半圆的圆心为点O,直径EF=6cm,P为弧EF的中点,Q是弧EF上的动点.
![](https://img.xkw.com/dksih/QBM/2019/5/19/2206894950752256/2213418667835392/STEM/59534eac8b6a48c8aebe6ea7ee1f7735.png?resizew=332)
发现:DQ的最小值是 cm;DQ的最大值为 cm;
探究:沿直线CD向左平移半圆.
(1)当P落在▱ABCD的边上时,区域半圆与其重合部分的面积;
(2)半圆向左以每秒3cm的速度平移,以图所在位置开始平移,运动时间为ts,当其与▱ABCD的边(CD边除外)相切时,求t的值.
![](https://img.xkw.com/dksih/QBM/2019/5/19/2206894950752256/2213418667835392/STEM/59534eac8b6a48c8aebe6ea7ee1f7735.png?resizew=332)
发现:DQ的最小值是 cm;DQ的最大值为 cm;
探究:沿直线CD向左平移半圆.
(1)当P落在▱ABCD的边上时,区域半圆与其重合部分的面积;
(2)半圆向左以每秒3cm的速度平移,以图所在位置开始平移,运动时间为ts,当其与▱ABCD的边(CD边除外)相切时,求t的值.
2018·河北·三模 查看更多[1]
更新时间:2019-05-28 15:14:43
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【知识点】 圆与四边形的综合(圆的综合问题)
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解答题-应用题
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较难
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名校
【推荐1】问题提出
(1)如图①,点
为
外一点,点
在
上,
的半径为
,
,则
的最大值是 ,
的最小值是 ;
问题探究
(2)如图②,在正方形
内部有一点
,连接
,
,
,求
的长;
问题解决
(3)如图③,所示区域为某小区一块空地,
,
,
,
,
所对的圆心角为
,该物业管理部门计划在这块空地内部点
处建造一个凉亭,同时在
上取一点
,从
点分别向
、
、
处修建文化长廊,为节约修建文化长廊的成本,不考虑其他因素,是否存在这样的点
,使得
最小,若存在,请求
的最小值;若不存在,请说明理.
(1)如图①,点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.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/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56dd0d3555f28d7cae026d46d23d101e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b66a5b7813e902306477f91f9f4084cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b66a5b7813e902306477f91f9f4084cd.png)
问题探究
(2)如图②,在正方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e0f73b3c63084d9c032802e01f9a168.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b887d1ee136ff6a805c1b2a9158ac207.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d53f732a570a2eeaf2625ccf65c2c99c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
问题解决
(3)如图③,所示区域为某小区一块空地,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d20fec32122b4a70b993976201c9ba9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ec5050ce60c9b2590b2914e21f6b609.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2a06b2fa20b690effa23789ea66bf6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7baa341d9c9a4190851a9eb244404ccc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed41d321f4c0717ac5b443aad942d9a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed41d321f4c0717ac5b443aad942d9a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
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![](https://img.xkw.com/dksih/QBM/2021/3/9/2674329675800576/2675456833495040/STEM/c482716ca20e44b48a17610d2b3ad636.png?resizew=433)
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解答题-问答题
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较难
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【推荐2】在矩形ABCD中,AB=2,∠ACB=30°,将矩形ABCD绕点A逆时针方向旋转,得到矩形AB′C′D′,记旋转角为α(0<α<90°).
(I)如图①,当B'C'过点D时,求△ADC'的面积S的值;
(Ⅱ)如图②,当点B的对应点B'落在AC上时,在B′C′上取点E,使B'E=AB.
①求∠EBB'的大小;
②求BE的长(直接写出结果即可).
(I)如图①,当B'C'过点D时,求△ADC'的面积S的值;
(Ⅱ)如图②,当点B的对应点B'落在AC上时,在B′C′上取点E,使B'E=AB.
①求∠EBB'的大小;
②求BE的长(直接写出结果即可).
![](https://img.xkw.com/dksih/QBM/2019/11/28/2343512749899776/2345102632353792/STEM/c7ec8c940aca415ab6b9710296a860d6.png?resizew=356)
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