二面角的平面角可以转化为两异面直线所成角(或补角),也可转化为线面角(或补角),三种空间角其实质是统一的.具体认识视角如下:(1)二面角α-l-β的平面角:在棱l上取一点O,然后在两个半平面内分别作过棱l上O点垂线OA、OB,∠AOB为二面角α-l-β的平面角. The dihedral angle of the plane can be converted into two different straight lines formed by the angle (or supplementary angle), can also be converted into line angle (or fill angle), the three space angle is essentially uniform.pecific perspectives are as follows: (1) dihedral angle α-l-β plane angle: take a point O on the edge l, and then in the two half-plane respectively over the edge of the o point O vertical line OA, OB, ∠ AOB for the dihedral angle The plane angle α-l-β.