立体几何中有些求解题,其图形常常是不够完整的或直观性很差,给学生解题带来了困难。如果我们注意题图的特征,恰当地配置直观的辅助立体图,将原有图形或图形的一部分恢复成正(长)方体、三棱柱(锥)、平行六面体,…等等我们所熟知的图形(其图形的性质和某些数量关系也很明显),从而可获取解决问题的途径。下面举几例说明之。 Some problems in the three-dimensional geometry, the graphics are often not complete or intuitive, giving students difficult problems. If we pay attention to the characteristics of the question map, properly configure an intuitive auxiliary perspective view, and restore part of the original figure or figure to positive (long) square, triangular prism (cone), parallelepiped, ... etc. The relationship between the nature of the graph and certain quantities is also obvious, so that the solution to the problem can be obtained. Here are a few examples to illustrate.