When solving geometric problems with complex or scattered conditions, it is often necessary to turn unfamiliar problems into familiar problems and complex problems into simple problems, and properly concentrate the scattered conditions through some transformation means (for example, making appropriate auxiliary lines), so as to establish links between lines, angles and shapes and solve problems.

Second, the equation holds that:

When it is not easy to directly find the unknown quantity of proving and calculating problems in geometry, we can think of relevant theorems according to the conditions given by the topic, and combine the graph, choose the unknown quantity that is convenient to combine conditional conclusions, graphs, theorems and definitions as X, and seek equivalence relations from multiple angles (the position relationship between graphs and theorems, the relationship between known conditions and theorems, etc.). ) establish equations or equations to solve problems.

Third, the combination of numbers and shapes:

Geometric figures in rectangular coordinate system can often combine plane geometric figures with function images with the help of coordinates of points, analytical expressions of straight lines and properties of functions, understand numbers through shapes, understand shapes with numbers, and intuitively deepen the understanding of quantitative relations with graphics, thus simplifying the calculation problems in geometry.

Fourth, the idea of classified discussion.