平面是立体几何的基础,点、线、面要素的位置和数量关系通常要化归到平面中来解决,在解决问题中起关键性作用的平面,可称为核心平面.在实际问题中,哪些平面可以成为核心平面呢?我们不妨从以下几个视角找找看. The plane is the basis of the three-dimensional geometry, and the position and quantity relationship of points, lines, and surface elements is usually transferred to the plane to solve. The plane that plays a key role in solving problems can be called the core plane. In practical problems, Which planes can become the core plane? Let’s look at the following perspectives.