[tex]\bf \begin{array}{ccllll}
model&actual\\
\textendash\textendash\textendash\textendash\textendash\textendash&\textendash\textendash\textendash\textendash\textendash\textendash\\
1&6\\
1\frac{1}{4}&x
\end{array}\implies \cfrac{1}{1\frac{1}{4}}=\cfrac{6}{x}
\\\\\\
1\frac{1}{4}\implies \cfrac{1\cdot 4+1}{4}\implies \cfrac{5}{4}\qquad thus
\\\\\\
[/tex]
[tex]\bf \cfrac{1}{\frac{5}{4}}=\cfrac{6}{x}\implies \cfrac{\frac{1}{1}}{\frac{5}{4}}=\cfrac{6}{x}\implies \cfrac{1}{1}\cdot \cfrac{4}{5}=\cfrac{6}{x}\implies \cfrac{4}{5}=\cfrac{6}{x}
\\\\\\
x=\cfrac{5\cdot 6}{4}[/tex]