1.PA垂直CD,CD垂直AD => CD垂直平面PAD => 平面PCD垂直平面PAD => A-PD-C=90
2.PA垂直AD,AD垂直AB => AD垂直平面PAB => 平面PAD垂直平面PAB => B-PA-D=90
3.PA垂直ABC => B-PA-C的二面角为BAC,即45
4.设AC、BD交于O,作OE垂直PC于E
AC垂直BD,PA垂直BD => BD垂直平面PAC => BD垂直PC
OE垂直PC => PC垂直BED => BED为B-PC-D的二面角
PAC相似OEC => OE=根号6/6AB => OE/OB=1/根号3 => OEB=OED=60 => BED=120