平行四边形是一类特殊的四边形,它的特殊性体现在对边相等、对角相等、邻角互补、对角线互相平分,因此,由平行四边形可以得到很多的相等线段、相等角.同学们要学会用对比的方法区分平行四边形的判定定理和性质定理,正确地运用相关的定理解决相关问题.一、利用平行四边形的性质与判定求解 Parallelogram is a special type of quadrilateral, its particularity is reflected in the same side of the opposite, the same angle, adjacent to each other, diagonals bisect each other, therefore, from the parallelogram can get a lot of equal segments, the same angle. To learn to distinguish the judgment of the parallelogram of the theorem and the nature of the theorem using the contrast method, the correct use of the relevant theorems to solve the related problems.First, the use of the nature of the parallelogram and determine the solution