CD: AB=GD: (BD+DG)3:AB=123*0.6:(BD+123*0.6)即：73.8AB=3BD+221.4 ①EF: AB=BF: (BD+DB)3:AB=127*0.6:(BD+1127*0.6)即：76.2AB=3BD+2028.6 ②由① ②得AB=753丈=1255步BD=18450丈= 30750步和你的答案一样
