解下面的比例.
问题描述：
解下面的比例.
1/2比1/5=1/4比X
0.8比4=X比8
3/4比X=3比12
36/X=54/3
2/9=8/X
1.25比0.25=X比1.6
答
① 1/2比1/5=1/4比X X = (1/5)×(1/4)÷(1/2) = 1/10② 0.8比4=X比8 X = 8×0.8÷4 = 1.6③ 3/4比X=3比12 X = (3/4)×12÷3 = 3④ 36/X=54/3 X = (54/3)÷36 = 1/2⑤ 2/9=8/X X = 8×9÷2 = 36⑥ 1.25比0.25=X...