空间距离和角一直是高考立体几何的必考内容.但有些题目直接求解比较困难,此时应改变思维方向,另寻解题思路.而用等体积变换法,变更三棱锥的顶点和底面,借助体积公式,常可化难为易,间接获解.一、求空间距离1.求点到平面的距离当点P在平面α内的射影位置不易确定时,可考虑构造以P为顶点,底面在α内的三棱锥,再用三棱锥的等体积变换法,求出它的高,即为点P到平面α的距离. Space distance and angle has always been the college entrance examination of the three-dimensional geometry of the necessary content.But some problems directly to solve more difficult, this time should change the direction of thinking, find another way to solve the problem.With the equal volume transform method, change the top and bottom of the triangular pyramid, With the help of the volume formula, it is often difficult to solve the problem easily and indirectly. First, find the distance between the space 1. Find the distance from the plane When the point P in the plane α is not easy to determine the location of the projective, consider the structure P as the vertex, the bottom The pyramid in α, and then use the equal volume transformation of the triangular pyramid, find its height, that is, the distance from the point P to the plane α.