To find the length of an arc with a central angle measure of 27 degrees, we can use the formula:
\text{Arc Length} = \left( \frac{\text{Central Angle}}{360^\circ} \right) \times (2\pi r),
where r is the radius of the circle.
Given that the central angle measure is 27 degrees, we can plug this into the formula:
\text{Arc Length} = \left( \frac{27^\circ}{360^\circ} \right) \times (2\pi r).
Now, simplify the fraction:
\frac{27}{360} = \frac{3}{40}.
So the formula becomes:
\text{Arc Length} = \left( \frac{3}{40} \right) \times (2\pi r) = \frac{3}{20} \pi r.
Therefore, the length of the arc with a central angle measure of 27 degrees is \frac{3}{20} \pi r , where r is the radius of the circle.
\boxed{\frac{3}{20} \pi r} is the length of the arc.