判别平行四边形的方法很多,可以按照边、角、对角线进行分类:按照边:两组对边分别平行;两组对边分别相等;一组对边平行且相等.按照角:两组对角相等.按照对角线:对角线互相平分.如果我们任意组合边、角和对角线的位置或者数量关系,也可以得到其它的平行四边形的判别方法,举例如 There are many ways to discriminate parallelograms. They can be classified according to edges, angles, and diagonals: according to edges: two sets of opposite edges are parallel; two pairs of opposite edges are equal; a set of opposite edges are parallel and equal. According to angle: two sets of pairs The angles are equal. According to the diagonal line: Diagonal lines are evenly divided. If we combine the position or quantity relation of edges, corners, and diagonals arbitrarily, we can also get other parallelograms. For example,