正方形比较特殊,导致了正方形有关题中的一些结论也比较特殊.在正方形内部,顶点处的45°角所对的边及边上的高就具有特殊的结论,这些结论是其他图形无法比拟的.结合具体问题,巧妙利用旋转,并借助三角形全等等知识,解决一些几何问题能收到不一般的解题效果,化繁就简,便捷高效.1.基本图形产生的背景先从一个引例说起:如图1所示,四边形ABCD是正方形,E、F两点分别在正方形的边BC、CD上,∠EAF The square is rather special, leading to some of the conclusions of the square is also quite special in the interior of the square, the angle of 45 ° at the edge of the edge and edge of the high has a special conclusion, these conclusions are unmatched by other graphics Combining with specific problems, using the rotation intelligently, and using the knowledge of triangle congruent and so on to solve some geometric problems, we can receive unusual solutions to the problems, Speaking: As shown in Figure 1, the quadrilateral ABCD is a square, E, F, respectively, two points on the side of the square BC, CD, ∠ EAF