直角梯形
中,
为
中点,沿
将
折起,使
重合于
,则
三棱锥的体积为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/696d11078798cb49aed6de1e04cbe2de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e50cc3ad2f67af7c6129a351345751f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77c5c74ec18b813d8cf8e020a6c3083f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab609a6574633ebabcff3e73fa862081.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cfcaa6cfbb0d35f1fc923a72936231a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/31/7ddf498b-6147-43aa-bdd8-6dacc114aa17.png?resizew=165)
更新时间:2021-01-28 22:03:28
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相似题推荐
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【推荐1】在《九章算术》中,将四个面都为直角三角形的三棱锥称之为鳖臑.已知在鳖臑
中,
平面
,
,则该鳖臑的外接球和内切球的半径之比为_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5d90f940f5693b22ddf2e7c761887d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39967d6f3aed6ce7b6643787795d451d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f690e1d6abbea460958aacc316729de6.png)
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【推荐2】如图,一个底面水平放置的倒圆锥形容器,它的轴截面是正三角形,容器内有一定量的水,水深为
.若在容器内放入一个半径为1的铁球后,水面所在的平面恰好经过铁球的球心
(水没有溢出),则
的值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eabd5f3a86afe49dcd70571e2b96cfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eabd5f3a86afe49dcd70571e2b96cfd.png)
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【推荐1】长方体
,
,
,若直线
与平面
所成角的正弦值为
,则
的值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1d20564320dc28e1b429ec389ccf309.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4a88b719166fcc1431f876bc8c5656c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/756d4d8a7051af5dae3ef56cb9e47c5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2122e3f1e76a635e58e4d54aa594c552.png)
![](https://img.xkw.com/dksih/QBM/2022/4/26/2966351585132544/2970693335785472/STEM/758ba9e4-0fe7-4bfb-bd86-a1476f14f539.png?resizew=160)
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【推荐2】在三棱锥
中,点O是点P在底面ABC内的射影.
(1)若PA=PB=PC,则O是△ABC___ 心;
(2)若PA⊥BC,PB⊥AC,则O是△ABC的___ 心.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
(1)若PA=PB=PC,则O是△ABC
(2)若PA⊥BC,PB⊥AC,则O是△ABC的
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【推荐3】在直四棱柱
中,底面
为边长为
的菱形,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c0c46783b77cce2bd4b45b9acc61884.png)
,
,点
在线段
上运动,且
,则以下命题正确的是_______ .
①当
时,三棱锥
的体积为
;
②点
在线段
上运动,点
到平面
的最大距离为
.;
③当二面角
的平面角为
时,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac1c3ea872a20fdc1843cb5ffce8a554.png)
④已知
,
为
的中点,当平面
与
的交点为
时,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d5bca00fa20e6e80480b9d06d2e52ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f7e8dd831f4edc711c0f7d5f078f625.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/56f132321bd26828ab57fadb588165fe.png)
①当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/441809d6ce2df21a85b390cdce9b1112.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f06e998447699f2e2176072ab3a4b602.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
②点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fe734023d4e70010a6b2cc3267cb86e.png)
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③当二面角
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d5bca00fa20e6e80480b9d06d2e52ee.png)
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④已知
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1885efcff0b903e314057dd153578600.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/d724f9d572e49704a97f582dfdd6e853.png)
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【推荐1】如图,正方体
的棱长为1,线段
上有两个动点
,
,且
,现有下列结论:①
;②平面
与平面
的交线平行于直线
;③异面直线
,
所成的角为定值;④三棱锥
的体积为定值,其中错误结论的是___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8f761d8eb1f2fa6975adcadca4b83fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cfbc0b5a8fbde804bd8425a4b76d207.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccc3bf74119692ac98eb24fcfa2a3f9f.png)
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【推荐2】如图,在正方体
中,点
为
上一动点(含端点),则下列四个结论:①
平面
;②
;③平面
平面
;④点
到平面
的距离为定值.其中一定正确的结论序号是__________ .
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【推荐3】如图,在长方体
中,点
在平面
内的射影为
,给出以下四个命题:①多面体
的外接球的表面积等于三棱锥
的外接球的表面积;②点
为
的垂心;③
;④
.其中所有正确命题的序号是________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccb45fee1f7160ebdafe57dfcb5c4733.png)
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