题目内容
A.45°或30° B.15°或75°
C.30°或60° D.15°或60°
B
A.45°或30° B.15°或75° C.30°或60° D.15°或60°
如果二面角α-l-β的平面角是锐角,点P到α、β和棱l的距离分别为,4和,那么这个二面角的大小为( )
A.45°或30°B.15°或75°C.30°或60°D.15°或60°