The formula for circumference is [tex]C = 2 \pi r[/tex]. We know the circumference and therefore we can plug that into the formula and solve for the radius.
[tex]\frac{1}{4} = 2 \pi r[/tex]
Lets divide by 2 first.
[tex]\frac{1}{8}= \pi r[/tex]
Next, lets divide by pi.
[tex]\frac{1}{8 \pi}= r[/tex]
Thus the answer is [tex]\frac{1}{8 \pi}[/tex] of a mile, which is approximately [tex]\frac{1}{25.13}[/tex] of a mile.