Check the picture below.
[tex]\cfrac{\stackrel{small}{S}}{\underset{Large}{L}}~~ = ~~\cfrac{\sqrt[3]{30}}{\sqrt[3]{240}}\implies \cfrac{S}{L}=\sqrt[3]{\cfrac{30}{240}}\implies \cfrac{S}{L}=\sqrt[3]{\cfrac{1}{8}}\implies \cfrac{S}{L}=\cfrac{\sqrt[3]{1}}{\sqrt[3]{8}} \\\\\\ \cfrac{S}{L}=\cfrac{1}{2}\implies \boxed{2S=L}~\hfill \stackrel{assuming~S=2.3}{2(2.3)=L}\qquad \stackrel{assuming~S=23}{2(23)=L}[/tex]
