Make a proportion. We know $4 is 100% and $4.32 is 100% plus taxes
so $4 = 100% and 4.32 = x
Cross multiply
4x= 4.32*100%
4x=432%
divide by 4
x=108%
since 4.32 is 100% + taxes, you have to get taxes alone by subtracting 108% by 100% leaving us with
8% sales tax
