如图,在多面体
中,四边形
是正方形,
平面
,
平面
,
.
![](https://img.xkw.com/dksih/QBM/2021/9/29/2818464416710656/2818549219246080/STEM/f69f68b64647406884ea59cb06a8fcb1.png?resizew=112)
(1)证明:平面
平面
.
(2)若
,求多面体
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8d2d217e9bcd059908f117dfc4d4259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fa3c61d6c19e187b4b824b6f5610cdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/563a54a1f1b9d82cc1b7bb4493b75b8f.png)
![](https://img.xkw.com/dksih/QBM/2021/9/29/2818464416710656/2818549219246080/STEM/f69f68b64647406884ea59cb06a8fcb1.png?resizew=112)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/812b915a549bf052c35dcb886242f83f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10fc7991ea17d54ff5f4445ac5699463.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
更新时间:2021-09-29 14:15:58
|
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【推荐2】如图,在四棱锥
中,侧棱
底面
,且底面
是边长为1的正方形,侧棱
,
与
相交于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/14/c1fd12c4-3ceb-4767-ab58-9f6ec224672f.png?resizew=203)
(1)证明:
;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10c83f8945042b9c8fb2fbdac9308d62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87a0b15556a1584c1b6b2768bbc9cbda.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/14/c1fd12c4-3ceb-4767-ab58-9f6ec224672f.png?resizew=203)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0d766d5c50f940cef0074fb60773bf6.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b9e73c210415e98ee9e778a171a0051.png)
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【推荐1】如图,在正方体
中,
分别是棱
,
,
,
的中点.
为梯形;
(2)求证:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/562b022158a42acccb8785cb75e5632a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea74bcb2642f3bdeb0f6d67b5baca43a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd61a751e4a47463b69923c771d085c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9189b58292cafb667004088b9b17c48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a85c632e08ce1b355808bc7a9ad9a051.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/573d3f133de9f6595657a128bbd2489a.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f20ac8cec1d644e24eb900915d8b724.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/573d3f133de9f6595657a128bbd2489a.png)
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【推荐2】如图,三棱柱
中
分别为
,
,
,
的中点,求证:
∥平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a22e1b56f9a5943ac7a36786e2db22b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c8ffe24cf9f327aeb241225ab15ab1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/21/9d962026-2725-47c2-ad9d-77c10bf4c50d.png?resizew=179)
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