To find how many miles she bike we multiply the amount she biked by the total length of the track:
[tex]\begin{gathered} \frac{1}{4}\cdot4\frac{1}{2}=\frac{1}{4}\cdot\frac{9}{2} \\ =\frac{9}{8} \\ =1\frac{1}{8} \end{gathered}[/tex]Therefore she biked 1 1/8 of a mile or 1.125 miles.