化归思想是极其重要的数学思想方法,在与图形面积有关的计算问题中,灵活运用化归思想可以有效解决许多问题,现举例分析如下:一、运用旋转变换化归例1如图1是一块直角三角形的土地,现在要在这块地上挖一个正方形的鱼塘AEDF,若已知剩余的两直角三角形两条斜边长分别为20cm和30cm, The idea of ​​transformation is an extremely important method of mathematics. In the computational problems related to the area of ​​the graph, the flexible use of the idea of ​​transformation can effectively solve many problems. An example analysis is as follows: First, the use of rotation transformations. In a right-angled triangle of land, it is now necessary to dig a square fish pond AEDF in this area. If the remaining two right-angled triangles are known to have a length of 20 cm and 30 cm, respectively,