a_60, formula_127, formula_128, formula_129, formula_130 为 formula_131, formula_132, formula_133, formula_134, formula_135。应用中点公式，点 formula_112, formula_113, formula_114, formula_115, formula_120, formula_122 位于使用距离公式，以及由于 formula_124 为整数，(见同余) 因此