Greetings!
We can solve this by creating an algebraic equation.
[tex]8/4=3/x[/tex]
Cross Multiply.
[tex]8*x=4*3[/tex]
[tex]8x=12[/tex]
Divide both sides by 8.
[tex](8x)/8=(12)/8[/tex]
The Answer Is:
[tex]x=1.5[/tex]
Three cakes would cost $1.50.
Hope this helps.
-Benjamin