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正四面体A﹣BCD的所有棱长均为12，球O是其外接球，M，N分别是△ABC与△ACD的重心，则球O截直线MN所得的弦长为（ ）
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高三下学期数学《》真题及答案
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已知四面体各面都是直角三角形且最长棱长则此四面体外接球的表面积为.
棱长为a的正四面体ABCD的四个顶点都在同一个球面上若过棱AB作四面体的截面交棱CD的中点于E且截
棱长为a的正四面体ABCD的四个顶点都在同一个球面上若过棱AB作四面体的截面交棱CD的中点于E且截
已知一个四面体的所有棱长都为2则该四面体的外接球表面积为________.
正四面体A﹣BCD的所有棱长均为12球O是其外接球MN分别是△ABC与△ACD的重心则球O截直线M
4
已知四面体的三组对棱分别相等且长分别为则此四面体的外接球的表面积为.
将长宽分别为2和1的长方形ABCD沿对角线AC折起得到四面体
-BCD,则四面体A.-BCD外接球的表面积为( ) A.3π
5π
10π
20π
求棱长为a的正四面体外接球与内切球的半径及表面积．
正四面体A.―BCD的棱长为1则A.到底面BCD的距离为.
正四面体的内切球与正四面体的四个面都相切的球与外接球过正四面体四个顶点的球的体积比为
1
∶
3
1
∶
9
1
∶
27
与正四面体的棱长无关
棱长为a的正四面体的内切球和外接球的半径分别为．
2015年·文昌中学模拟三正四面体ABCD的棱长为4E为棱BC的中点过E作其外接球的截面则截面面积
我们将四个面均为正三角形的四面体称为正四面体在正四面体ABCD中EF分别为棱ABCD的中点当时四面体
12π
4π
3π
6π
如图在四面体ABCD中AB⊥平面BCD△BCD是边长为6的等边三角形.若AB=4则四面体ABCD外接
已知正四面体的棱长为a则其外接球半径为．
求棱长为的正四面体的外接球半径和内切球半径.
已知正四面体P﹣ABC的棱长为1若DE分别是线段ABAC上的点且正四面体P﹣ABC外接球的球心O在
已知正四面体的棱长为1那么它的外接球半径为．
将长宽分别为4和3的长方形ABCD沿对角线AC折起得到四面体A.﹣BCD则四面体A.﹣BCD的外接球
5.00分正四面体四个面均为正三角形的四面体的外接球和内切球上各有一个动点PQ若线段PQ长度的最大
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