解立体几何问题主要有三种思路,一是借助立体图形自身的概念、性质、公式等直接去求解;二是将立体几何问题化归为平面几何问题间接求解;三是向量解题法.前两种思路的解题对策,均可通过构图法去实施,为叙述方便,不妨简称三种思路为第一类、第二类、第三类思路.一、第一类解题思? There are three ways to solve the three-dimensional geometry problem. One is to directly solve the concept, nature, formulas, etc. of the three-dimensional graphics; the other is to classify the three-dimensional geometry into indirect solution to the plane geometry problem; the third is the vector solution method. The first two The solution strategies of the ideas can be implemented through the composition method. For the convenience of narrative, it may be abbreviated as the first, second and third types of ideas. First, the first type of problem-solving thinking?