旋转法是一种重要的解题方法,它能使条件或结论中分散的有关元素(角、线段等)集中到同一三角形中,为问题的解决创造条件,使许多难解的几何题,经过恰当的旋转之后,变得迎刃而解.那么,在什么条件下可以利用旋转法来解题呢?一般地,若已知图形中含有共点的两条 Rotation method is an important problem solving method. It can concentrate the relevant elements (corners, line segments, etc.) scattered in the conditions or conclusions into the same triangle, creating conditions for the solution of the problem and making many difficult-to-solve geometric problems pass through. After the proper rotation, it becomes easy to solve. Then, under what conditions can you use the rotation method to solve the problem? Generally, if you know the graph contains two points in common