解题方法
1 . 若一个多面体的各面都与一个球的球面相切,则称这个球是这个多面体的内切球.在四棱锥
中,侧面
是边长为1的等边三角形,底面
为矩形,且平面
平面
.若四棱锥
存在一个内切球,设球的体积为
,该四棱锥的体积为
,则
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4764374bd2fb78e59cd0b283637baeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63055a5d6916f99d07fede49120753f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f737b04ce09bc7e1ed86dc9b3c85203b.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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2 . 正多面体是指各个面都是全等的正多边形,并且各个多面角都是全等的多面角,又称为柏拉图多面体,因为柏拉图及其追随者对它们所作的研究而得名.自然界中有许多的柏拉图多面体,如甲烷、金刚石分子结构模型都是正四面体,氯化钠的分子结构模型是正六面体,萤石的结晶体有时是正八面体,硫化体的结晶体有时会接近正十二面体的形状……柏拉图多面体满足性质:
(其中V,F和E分别表示多面体的顶点数,面数和棱数).
(2)如图所示的正方体
中,点
为正方体六个面的中心,假设几何体
的体积为
,正方体
的体积为
,求
的值;
(3)判断柏拉图多面体有多少种?并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a098e3851f80b3d3c273d34416c4778e.png)
(2)如图所示的正方体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/455cfa98d3b692be03f4e927d6a10b92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4d86e8d1bef7032ab58f3c85d47c28.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4764374bd2fb78e59cd0b283637baeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63055a5d6916f99d07fede49120753f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f737b04ce09bc7e1ed86dc9b3c85203b.png)
(3)判断柏拉图多面体有多少种?并说明理由.
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解题方法
3 . 已知正四面体
的棱长为2,M,N分别是棱
,
的中点,过M、N作正四面体
的截面
.有下列结论,其中正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88929f4ba0851730d5f941d426b87548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
A.异面直线![]() ![]() ![]() | B.![]() |
C.若截面![]() | D.截面![]() |
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解题方法
4 . 已知正方体
的棱长为1,点
在线段
上,过
作垂直于
的平面
,记平面
与正方体
的截面多边形的周长为
,面积为
,设
,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fe734023d4e70010a6b2cc3267cb86e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fe734023d4e70010a6b2cc3267cb86e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c88d9142df6ba8e43c1a93bd04a1362.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b658f610333d2cd189b8aaff108300f4.png)
A.截面可能为四边形 |
B.![]() ![]() |
C.![]() ![]() ![]() |
D.![]() ![]() ![]() |
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名校
5 . 在平面内有三个互不相交的圆,三个圆的半径互不相等.三个圆的方程分别为
.其中圆
与圆
的两条外公切线相交于点
,圆
与圆
的两条外公切线相交于点
,圆
与圆
的两条外公切线相交于点
,
表示直线AB的斜率,
表示直线AC的斜率,
表示直线BC的斜率.下列说法正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/298d4f4782916ab6c13f27ac0d024054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f3ffe7abc59e2f65d827c8eab8d36a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab94459e87c666facddbe1a23ae1899d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f3ffe7abc59e2f65d827c8eab8d36a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab94459e87c666facddbe1a23ae1899d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6defc43285a40f7ccb74c1cc04265eba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/423b7ae39db552e60ee8b1d27312306f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbf434334b09cc0fdd4e86e84e6ceb00.png)
A.存在![]() ![]() |
B.对任意![]() ![]() |
C.存在点![]() |
D.直线![]() ![]() ![]() |
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名校
解题方法
6 . 已知三棱锥
三条侧棱
,
,
两两互相垂直,且
,
,
分别为该三棱锥的内切球和外接球上的动点,则线段
的长度的最小值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41f65a7b230807b683d18bb7415473de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
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名校
7 . 如图,在矩形
中,
,
,
是线段AD上的一动点,将
沿着BM折起,使点
到达点
的位置,满足点
平面
且点
在平面
内的射影
落在线段BC上.
重合时,证明:
平面
;
(2)当
时,求二面角
的余弦值;
(3)设直线CD与平面
所成的角为
,二面角
的平面角为
,求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f656e1d1f68954e5f06de8958f6a9310.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a5e0a51c9e14fb246b0ba0b231c1e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7829855159327b2a87c3a424b3f7134a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f9e5a462c0ca3b9e2c603750a3b433b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f9e5a462c0ca3b9e2c603750a3b433b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69ce1507bc29b81f4a6594463c81ee0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1530d93834fbafba5f7217778ea90442.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f79e482d948bc813afde84be7ba96793.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3363c94be80317e56ad734e0a3490e8d.png)
(3)设直线CD与平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35247dcbb6b93e8338e53b7b402fe99b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3363c94be80317e56ad734e0a3490e8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4cd2f25e36ae0ed6a9f365f889a6342.png)
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名校
解题方法
8 . 如图,点
是棱长为2的正方体
的表面上一个动点,
是线段
的中点,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
A.若点![]() ![]() ![]() ![]() |
B.当点![]() ![]() ![]() ![]() |
C.当直线AP与AB所成的角为![]() ![]() ![]() |
D.当![]() ![]() ![]() ![]() ![]() |
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9 . 已知圆C过点
,
,
.
(1)求圆C的标准方程;
(2)若过点C且与x轴平行的直线与圆C交于点M,N,点P为直线
上的动点,直线PM,PN与圆C的另一个交点分别为E,F(EF与MN不重合),证明:直线EF过定点.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19b62194097ac66a5093c57fca2f5b4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbc43e72034cfce8e9d75b55c537287c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d7ffc33191f71a87fc60694a54227ac.png)
(1)求圆C的标准方程;
(2)若过点C且与x轴平行的直线与圆C交于点M,N,点P为直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da322ac8867e8a47c6588601078abf18.png)
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2024·全国·模拟预测
解题方法
10 . 已知四棱锥
的底面
是边长为
的正方形,
,
平面
,
为线段
的中点,若空间中存在平面
满足
,
,记平面
与直线
分别交于点
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90271643a96d65b3b092fbbdbd61eea0.png)
______ ,四边形
的面积为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/967f74b8993c61634ceed95edca05ffd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3dd3fc7dc95d1af9eafb1ea58dd48a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e049faf8852317b6c046904a39134c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a211a44ffb09c7413dac58e9cea70fd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90271643a96d65b3b092fbbdbd61eea0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a255eabf4d401236e1f1a9f35667ba9.png)
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