名校
解题方法
1 . 在棱长均相等的四面体
中,
为棱
(不含端点)上的动点,过点
的平面
与平面
平行.若平面
与平面
,平面
的交线分别为
,则
所成角的正弦值的最大值为________ .
![](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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7abd284f76d9f5769bc189508ce2572b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/280860dd039e1305a5ccc455f63e8223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/280860dd039e1305a5ccc455f63e8223.png)
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2 . 如图①,矩形ABCD中,
,
,E,F分别为AB,DC的中点.将四边形AEFD沿EF折起至四边形
的位置,如图②.
在平面
上的射影为
的中点,则三棱锥
的体积为________ ;
(2)当平面
与平面
垂直时,作正方体
如图③.若平面
平面
,且平面
截该正方体所得图形的面积记为
,则
的最大值为________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6ccd49a0c3ccd22943c15ed7bf0f4c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a03952d664fba91020fc5f3bcf2f9746.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/945fbe95bfb4e8e37e619e2d767efef6.png)
(2)当平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6ccd49a0c3ccd22943c15ed7bf0f4c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a03952d664fba91020fc5f3bcf2f9746.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0bc49d40da6aebbb370be30fa2e6c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/414844edd458857bdfc80bffa61cbf9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecba239ca1f109309bf14fab784ea827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
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3 . 已知正三棱柱
的所有顶点都在表面积为
的球的球面上,
,点
为棱
的中点,点
是侧面
内的一点,且
平面
,则线段
的最小值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9eea5a7fb6fb9ebab654b7c16706c8a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f1f229274a6e17977cc047814212589.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ad7c84ff3f05cb53cfce047e873609e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea848cd2aa3a464618020475097949fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6655c413f509068d30b165f9d92bdba0.png)
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解题方法
4 . 如图,已知四面体
的各条棱长均等于
分别是棱
的中点.若用一个与直线
垂直,且与四面体的每一个面都相交的平面
去截该四面体,由此得到一个多边形截面
,当截面
面积最大时,四棱锥
的体积为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2612d8c87010adfe87728a591b63e3a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d93949d8a15aca4e79cedb978590571.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a315e4b5963127bf8550cde03ca1966d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a315e4b5963127bf8550cde03ca1966d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9df6a9fadc944f228ec12642a194f35e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/6/17/50b73dc0-268c-4c34-bdb4-8ac147cdf3e5.png?resizew=168)
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5 . (易混易错辨析题)下列命题中正确的有________
①四边形可以确定一个平面;
②若一条直线与一个平面平行,则这条直线平行于这个平面内的任意一条直线;
③若两平面平行,则一个平面内的任一直线必平行于另一个平面;
④若一条直线垂直于平面内的无数条直线,则这条直线与这个平面垂直;
⑤过直线外一点,有且只有一个平面与这条直线垂直;
⑥过直线外一点,有且只有一个平面与这条直线平行.
①四边形可以确定一个平面;
②若一条直线与一个平面平行,则这条直线平行于这个平面内的任意一条直线;
③若两平面平行,则一个平面内的任一直线必平行于另一个平面;
④若一条直线垂直于平面内的无数条直线,则这条直线与这个平面垂直;
⑤过直线外一点,有且只有一个平面与这条直线垂直;
⑥过直线外一点,有且只有一个平面与这条直线平行.
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6 . 如图,若正三棱柱
的底面边长为
,对角线
的长为
,点
为
的中点,则点
到平面
的距离为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3304e23f3b0f9569c4140ca89b6498.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07ae0b4264da6a8812454ffd2f20d94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c01fdc7bc471af0b264a04aef0823e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73845d4d663b3de0b281611fe2c762fe.png)
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解题方法
7 . 在棱长为1的正方体
中,E,F分别为
和
的中点,
是侧面
内一点,若
平面
,则线段
长度的取值范围是________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/183d4a4db2be531d09a180b36515ff75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/134ef0b1a2669a09f05bd4dc2496f706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5563473602e1b17d582a165b7b7b6b2.png)
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8 . 《九章算术》是我国古代数学名著,它在几何学中的研究比西方早
多年,在《九章算术》中,将底面为直角三角形且侧棱垂直于底面的三棱柱称为堑堵,将底面为矩形且一侧棱垂直于底面的四棱锥称为阳马,将四个面均为直角三角形的四面体称为鳖臑.如图在堑堵
中,
,
,
,
分别为棱
,
的中点,则下列说法正确的是______ .(只填序号)
①四面体
为鳖臑
②
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea848cd2aa3a464618020475097949fc.png)
③若
,则
与
所成角的正弦值为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaa42621cd6793e7f3673fdb49bc3123.png)
④三棱锥
的外接球的体积为定值![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a30821635432b069b6c2bf74fa09552f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dadc63e6e33743ce590ed968948a5a58.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30dbd22b0cbb47c914c42a4355e3ca98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
①四面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/861d61d2b7b16e12fd97f870fb3fa522.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/063510e3c1fb6a7ccc3b8e3e3c7d660e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea848cd2aa3a464618020475097949fc.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68b40d0d2f3cdd8981bb792ad87efb42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaa42621cd6793e7f3673fdb49bc3123.png)
④三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/861d61d2b7b16e12fd97f870fb3fa522.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a30821635432b069b6c2bf74fa09552f.png)
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9 . 如图所示,在长方体
中,
,
.一平面截该长方体,所得截面为OPQRST,其中O,P分别为AD,CD的中点,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73a56f5a416cac043efa6d643f297b06.png)
______ ,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51e0d8f378c1625b6039dfacb0013c69.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27db558e8db4c957654c8e5cecd2d2dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad1a56baf43ffdf67bc8460856e31fec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24793094279349667002e7cc87682970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73a56f5a416cac043efa6d643f297b06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51e0d8f378c1625b6039dfacb0013c69.png)
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解题方法
10 . 如图,在长方体
中,
,
,M,N分别为
,
的中点,则三棱锥
的体积为_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27db558e8db4c957654c8e5cecd2d2dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e55a2310cbba5e050488cd9296eb195d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbbb6e880775a36ca70c5edb0f488f80.png)
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