所谓等积变形 ,就是仅通过改变图形的位置或形状 ,而保持其面积不变的一种几何变形 .它通过对图形的分割与组合、整体与局部之间的相互转化 ,从而将不规则图形转化为规则图形 ,以达到优化图形迅速解题的目的 .近年来 ,各地的中考面积类试题中 ,有不少是以扇形、弓形面积为基础 The so-called equal-area deformation is a kind of geometric deformation that maintains its area unchanged only by changing the position or shape of the graph. It transforms the graph by dividing and combining the graph and transforming the whole and the part. Converted into regular graphics to achieve the goal of optimizing the graphs quickly. In recent years, many of the exams for the area of ​​local examinations have been based on fan-shaped and arched areas.