阅读材料:如图1,若点P是⊙O外的一点,线段PO交⊙O于点A,则PA长是点P与⊙O上各点之间的最短距离.
证明:延长PO交⊙O于点B,显然PB>PA.
如图2,在⊙O上任取一点C(与点A,B不重合),连结PC,OC.
∵PO<PC+OC,
且PO=PA+OA,OA=OC,
∴PA<PC
∴PA 长是点P与⊙O上各点之间的最短距离.
由此可以得到真命题:圆外一点与圆上各点之间的最短距离是这点到圆心的距离与半径的差.请用上述真命题解决下列问题.
(1)如图3,在Rt△ABC中,∠ACB=90°,AC=BC=2,以BC为直径的半圆交AB于D,P是
上的一个动点,连接AP,则AP长的最小值是 .
(2)如图4,在边长为2的菱形ABCD中,∠A=60°,M是AD边的中点,点N是AB边上一动点,将△AMN沿MN所在的直线翻折得到△A′MN,连接A′C,①求线段A’M的长度; ②求线段A′C长的最小值.
证明:延长PO交⊙O于点B,显然PB>PA.
如图2,在⊙O上任取一点C(与点A,B不重合),连结PC,OC.
∵PO<PC+OC,
且PO=PA+OA,OA=OC,
∴PA<PC
∴PA 长是点P与⊙O上各点之间的最短距离.
由此可以得到真命题:圆外一点与圆上各点之间的最短距离是这点到圆心的距离与半径的差.请用上述真命题解决下列问题.
(1)如图3,在Rt△ABC中,∠ACB=90°,AC=BC=2,以BC为直径的半圆交AB于D,P是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83bb3820bab977db734f4335e4fde720.png)
(2)如图4,在边长为2的菱形ABCD中,∠A=60°,M是AD边的中点,点N是AB边上一动点,将△AMN沿MN所在的直线翻折得到△A′MN,连接A′C,①求线段A’M的长度; ②求线段A′C长的最小值.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/31/6f34bfca-f372-4468-b53a-6cb8b3403f24.png?resizew=323)
更新时间:2018-02-06 21:57:05
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【推荐1】如图,已知等边△ABC 的边长为8,点 P 是 AB 边上的一个动点(与点 A、B 不重合).直线 l 是经过点 P 的一条直线,把△ABC 沿直线 l 折叠,点 B 的对应点是点B'.当 PB=6 时,在直线 l 变化过程中,求△ACB'面积的最大值.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/1b2b2b08-3056-4968-a099-bc1571f61622.png?resizew=120)
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【推荐2】如图,
的面积为12,
,
.点M在边AB上(点M与点A不重合),连结DM,作点A关于直线DM的对称点
,连结
、
.
![](https://img.xkw.com/dksih/QBM/2022/5/31/2991227185659904/2992254938161152/STEM/7f74854a-64e7-44a1-81f5-ea9f8eba5bc3.png?resizew=224)
(1)点D到直线AB的距离是______.
(2)设点
到直线BC的距离为d,求d的最小值.
(3)当点
落在
的边上时,求AM的长.
(4)当直线
与
的一边垂直时,直接写出AM的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a88d4e0249bd16d48eda01331d2d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d5a2cd05e4476fc72271e8fdb59a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42198b8e646ccfbbec323fd364c4d90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a21897349d3d7c94419692106887153.png)
![](https://img.xkw.com/dksih/QBM/2022/5/31/2991227185659904/2992254938161152/STEM/7f74854a-64e7-44a1-81f5-ea9f8eba5bc3.png?resizew=224)
(1)点D到直线AB的距离是______.
(2)设点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
(3)当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
(4)当直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42198b8e646ccfbbec323fd364c4d90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
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【推荐3】【问题呈现】在学习《圆》这一章时,小明遇到了这样一个问题:如图
,已知
半径是
,点
是
上的一个动点,点
是平面内一点,
,求证:线段
的最大值为
.
【问题解决】经过分析,如图
,小明将
延长交
于点
,并猜想此时
最大,为了验证这个猜想,小明想利用如下方法来解决,下面是部分证明过程,请补全缺失的部分.
证明
如图
, 在
上任意取一点
点
不与点
重合
, 连结
、
,
证明过程缺失
则
,
则此时,
最大, 最大值为
.
【问题延申】如图
, 在
中,
,
,
, 点
是边
上的一个动点, 连结
, 过点
作
于点
, 连结
, 则线段
的最小值是 .
【拓展提升】如图
,某景区有一片油菜花地,形状由
和以
为直径的半圆两部分构成, 已知
米,
,
, 为了方便游客游览, 该景区计划对油菜花地进行改造,根据设计要求,在半圆上确定一点
,沿
修建小路,并在
中点
处修建一个凉亭,沿
修建仿古长廊,由于仿古长廊造价很高、为了控制成本,景区要求仿古长廊
的长度尽可能短,若不考虑其他因素,则仿古长廊
最短为 米.(结果保留根号)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9ccea461315a9d05aa0193b937d4bfe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9ccea461315a9d05aa0193b937d4bfe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0eabf2b71d1c53cb37efdf9bcc4ebdb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e61620a272dada8d4b9a9fab6379dfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c79c562343bd2362a979662d3865020c.png)
【问题解决】经过分析,如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b73be30f639b301cf797d6e8d04a568d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9ccea461315a9d05aa0193b937d4bfe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e61620a272dada8d4b9a9fab6379dfd.png)
证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b4e1b8436cf2a739c7ba5d3c68165d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9ccea461315a9d05aa0193b937d4bfe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7986887b83aab178ae991d8e4c2696e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30513ea48bc1ef3ae78adac83d894f14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d62e8aadaadebf1454fde21a390ebdea.png)
证明过程缺失
则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eed333cde3f8aa226666e25e5a1badc.png)
则此时,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e61620a272dada8d4b9a9fab6379dfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92a76e7c07b0520f70d1cd7bc6d8e1f6.png)
【问题延申】如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29c7d01c3618d579121d95d41a63c565.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/377f5c10cf527c87ab06bff61384f7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65e34f3fbb1adf23cf81d7005f4387a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93c3f982d999937891eec4cb22d62e5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38ddb320a6ab6b51ca80ddc07d4fcc0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8120f2eeb724c756b5f84a14c6df527.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8120f2eeb724c756b5f84a14c6df527.png)
【拓展提升】如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa60765f115c2a4ac9a12a2808ec1640.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29c7d01c3618d579121d95d41a63c565.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e12142a1fe7a56258c769c7f288e8c24.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9f79d7939c88e9702962e5917cad290.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9f79d7939c88e9702962e5917cad290.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8120f2eeb724c756b5f84a14c6df527.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8120f2eeb724c756b5f84a14c6df527.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8120f2eeb724c756b5f84a14c6df527.png)
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【推荐1】直角三角形纸片ABC中,∠ACB=90°,AC≤BC,如图,将纸片沿某条直线折叠,使点A落在直角边BC上,记落点为D,设折痕与AB、AC边分别交于点E、F.
(1)如果∠AFE=65°,求∠CDF的度数;
(2)若折叠后的△CDF与△BDE均为等腰三角形,那么纸片中∠B的度数是多少?写出你的计算过程.
(1)如果∠AFE=65°,求∠CDF的度数;
(2)若折叠后的△CDF与△BDE均为等腰三角形,那么纸片中∠B的度数是多少?写出你的计算过程.
![](https://img.xkw.com/dksih/QBM/2021/9/9/2804549372248064/2805262575362048/STEM/2292a2e4-0ed2-4e11-aba7-953369bb42b6.png)
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【推荐2】如图,将一张长方形纸片分别沿着EP,FP对折,使点B落在点B′,点C落在点C′.
(1)若点P,B′,C′在同一直线上(如图1),求两条折痕的夹角∠EPF的度数;
(2)若点P,B′,C′不在同一直线上(如图2),且∠B′PC′=10°,求∠EPF的度数.
(1)若点P,B′,C′在同一直线上(如图1),求两条折痕的夹角∠EPF的度数;
(2)若点P,B′,C′不在同一直线上(如图2),且∠B′PC′=10°,求∠EPF的度数.
![](https://img.xkw.com/dksih/QBM/2018/7/16/1989765236629504/1991222698565632/STEM/0231e766797e45dca3d6ed1d25b5cee5.png?resizew=205)
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【推荐1】已知:如图,M是
的中点,过点M的弦
交弦
于点C,设
的半径为
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/4/90ba1ce2-7f52-44db-b2e1-dd5f06170ff0.png?resizew=140)
(1)求圆心O到弦
的距离;
(2)求
的度数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16d65cecaf8a3dc2953f4109c75a981e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](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/095ab4a92bf822e175d370e6d0c8a730.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eaeaa54df10ccadfa4edca7871c972f3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/4/90ba1ce2-7f52-44db-b2e1-dd5f06170ff0.png?resizew=140)
(1)求圆心O到弦
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/474c0dc8c11624c4997e48b143bb09a5.png)
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【推荐2】如图,
是
的直径,
、
分别与
相切于点
、
,
交
的延长线于点
,
⊥交
的延长线于点
,交
于点
,连结
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/8/135fe28b-5db4-48e6-96a0-2978f3339549.png?resizew=195)
(1)求证:
;
(2)若
,
,求
的半径和线段
的长.
![](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/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.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/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97cac0ca225660e07f78a9ff2c2c1ed8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef49a3ca580a144cc65a609c167facc1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/8/135fe28b-5db4-48e6-96a0-2978f3339549.png?resizew=195)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de480e2cd00d41db04cfec853c125cfa.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b887d1ee136ff6a805c1b2a9158ac207.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f919e471ffd4d5e27d8c6f7fd507e45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
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