1:X=0.4:3
0.4 X=1x3
0.4 X= x
0.4 X=
X=÷0.4
X=x
X=10
0.6:X=1.5:10
1.5 X=0.6x10
1.5 X=6
X=6÷1.5
X=4
X:1.2=5/12:5
5 X=1.2x5/12
5 X=0.5
X=0.5÷5
X=0.1
0.75:X=3:12
3 X=0.75x12
3 X=9
X=9÷3
X=3
1/2:1/3=1/4:X
1/2 X=1/3x1/4
1/2 X=1/12
X=1/12÷1/2
X=1/64.2/7=54/X4.2 X=7x54 4.2 X=378 X=378÷4.2X=90