To find the scale factor from circle X to circle Z, we can compare their circumferences.
Circle X has a circumference of \(12\pi\), and circle Z has a circumference of \(6\pi\).
To find the scale factor, we can divide the circumference of circle Z by the circumference of circle X:
\[ \text{Scale factor} = \frac{\text{Circumference of circle Z}}{\text{Circumference of circle X}} = \frac{6\pi}{12\pi} \]
Simplifying this gives:
\[ \text{Scale factor} = \frac{6}{12} = \frac{1}{2} \]
Therefore, the scale factor from circle X to circle Z is \(\frac{1}{2}\).