核心知识梳理重点掌握轴对称、轴对称图形、平移、旋转、中心对称和中心对称图形的有关概念,注意轴对称和轴对称图形、中心对称和中心对称图形的区别和内在联系,并理解相关性质.平移的性质:(1)平移前后,对应点连接的线段平行且相等;(2)对应线段平行(或共线)且相等,对应角相等;(3)平移后的图形 Focus on the core knowledge Combine the relevant concepts of axisymmetric, axisymmetric, translation, rotation, center symmetry and center symmetry graphics, pay attention to the difference and internal connection of axisymmetric and axisymmetric graphics, center symmetry and center symmetry graphics, and understand the related properties . The nature of translation: (1) Before and after translation, the line segments connected to the corresponding points are parallel and equal; (2) The corresponding line segments are parallel (or collinear) and equal and the corresponding angles are equal; (3)