[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}\\\\
-------------------------------\\\\
%. Length Hours 15 3 20 4
\begin{array}{ccllll}
length&hours\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
15&3\\
20&4
\end{array}\\\\
-------------------------------\\\\[/tex]
[tex]\bf \textit{H increases as L increases}\implies H=kL
\\\\\\
\textit{from the table above, we also know that }
\begin{cases}
L=15\\
H=3
\end{cases}
\\\\\\
3=k15\implies \cfrac{3}{15}=k\implies \cfrac{1}{5}=k\quad thus\quad \boxed{H=\cfrac{1}{5}L}
\\\\\\
\textit{now, what is H when L = 2}\qquad H=\cfrac{1}{5}\implies \cdot 2[/tex]
