[tex]\bf \qquad \qquad \textit{ratio relations}
\\\\
\begin{array}{cccllll}
&Sides&Area&Volume\\
&-----&-----&-----\\
\cfrac{\textit{similar shape}}{\textit{similar shape}}&\cfrac{s}{s}&\cfrac{s^2}{s^2}&\cfrac{s^3}{s^3}
\end{array}\\\\
-----------------------------\\\\[/tex]
[tex]\bf \cfrac{\textit{similar shape}}{\textit{similar shape}}\qquad \cfrac{s^2}{s^2}=\cfrac{20}{180}\implies \left( \cfrac{s}{s} \right)^2=\cfrac{20}{180}\implies \cfrac{s}{s}=\sqrt{\cfrac{20}{180}}
\\\\\\
\cfrac{s}{s}=\cfrac{\sqrt{20}}{\sqrt{180}}\implies \cfrac{s}{s}=\cfrac{2\sqrt{5}}{6\sqrt{5}}\implies \cfrac{s}{s}=\cfrac{2}{6}\implies \cfrac{s}{s}=\cfrac{1}{3}[/tex]