[tex]\bf \qquad \qquad \textit{direct proportional variation}\\\\
\textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby
\begin{array}{llll}
k=constant\ of\\
\qquad variation
\end{array}\\\\
-------------------------------\\\\
\textit{we also know that }
\begin{cases}
y=12\\
x=16
\end{cases}\implies 12=k16\implies \cfrac{12}{16}=k
\\\\\\
\cfrac{3}{4}=k\qquad therefore\qquad \boxed{y=\cfrac{3}{4}x}
\\\\\\
\textit{when x = 6, what is \underline{y}?}\qquad y=\cfrac{3}{4}(6)[/tex]
