其它
The ratio of the perimeter of a rectangle to the length of one of its sides is~$14:3$. If the area is 27 square inches, how many inches long is one of the longer sides? 
Overseas Competition->Knowledge Point->Calculation Modules->Ratios and Proportions
$\dfrac{2\left( x+y\right)}{x}=\dfrac{14}{3}\textbackslash{} \textbackslash{} \Rightarrow\textbackslash{} \textbackslash{} \dfrac{x+y}{x}$~$=\dfrac{7}{3}\textbackslash{} \textbackslash{} \Rightarrow\textbackslash{} \textbackslash{} 1+\dfrac{y}{x}=1+\dfrac{4}{3}$  $\Rightarrow\textbackslash{} \textbackslash{} \dfrac{y}{x}=\dfrac{4}{3}\textbackslash{} \textbackslash{} \Rightarrow\textbackslash{} \textbackslash{} \dfrac{y\times y}{x\times y}=\dfrac{4}{3}$  The area is~$x\times y=27\textbackslash{} \textbackslash{} \Rightarrow\textbackslash{} \textbackslash{} \dfrac{y\times y}{27}=\dfrac{4}{3}\textbackslash{} \textbackslash{} \Rightarrow\textbackslash{} \textbackslash{} y\times y=36\textbackslash{} \textbackslash{} \Rightarrow\textbackslash{} \textbackslash{} y=6$ 