Answer :
[tex]4\frac{1}{2}\text{ is to 4 as x is to 12}[/tex][tex]\begin{gathered} 4\frac{1}{2}=4 \\ x=12 \end{gathered}[/tex]
the next thing is to cross multiply
[tex]\begin{gathered} \frac{9}{2}=4 \\ x=12 \\ \frac{9}{2}\times12=4\times x \\ 54=4x \\ \text{Dividing both sides by 4} \\ x=\frac{54}{4} \end{gathered}[/tex][tex]x=13\frac{1}{2}[/tex]Hence the value of x is 13 1/2