1 mile is aproximately equivalent to 1.61 kilometers. To find the equivalent length of 12.5 km, we can use the next proportion:
[tex]\frac{1\text{ mile}}{x\text{ miles}}=\frac{1.61\text{ km}}{12.5\text{ km}}[/tex]Solving for x:
[tex]\begin{gathered} 1\cdot12.5=1.61\cdot x \\ \frac{12.5}{1.61}=x \\ 7.77\text{ miles = x} \end{gathered}[/tex]