4.32+【（伏兄圆28.4-25.9）×0.5】缺塌÷0.1＝4.32+（尘运2.5x0.5）x10=4.32+12.5=16.82 bc-ac=c(b-a)=0.4x(5.5-1.6)=0.4x3.9=1.56
