2.8：五分之四=0.7：X 用比例解
问题描述：
2.8：五分之四=0.7：X 用比例解
答
2.8：五分之四=0.7：X
2.8x=0.7*4/5
x=0.7*0.8/2.8=0.2
答
2.8：五分之四=0.7：X
2.8x=4/5×0.7
x=0.2
答
2.8：五分之四=0.7：X
2.8x=0.8×0.7
2.8x=0.56
x=0.2
答
2.8：五分之四=0.7：X
2.8：0.8=0.7：X
2.8x=0.8*0.7
2.8x=0.56
x=0.2
祝学习进步，望采纳~~