二面角是高考考查的重点,正确的求二面角的大小又是个难点,如何突破这个难点将成为关键.下面就具体的例题,说说求二面角的常用策略.1定义法即在二面角的棱上找一点,在二面角的两个面内分别作棱的垂线,两条垂线所夹的角即为二面角的平面角. Dihedral angle is the focus of the college entrance examination test, the correct size of the dihedral is a difficult point, how to break through this difficult will become the key to the following specific examples, to talk about the commonly used strategy for dihedral 1. Definition of the law that is Find the dihedral angle of the edge, respectively, in the two sides of the dihedral angle of the prism respectively, the angle between the two vertical lines is the dihedral angle of the plane.