If found the image that accompanies this problem, the central angle was 60°. Since the circumference of a circle is always 360°, the minor arc represents 60°/360° of the circle.
48 cm / (60°/360°) = 48 cm / (1/6) = 48 cm * 6/1 = 48 cm * 6 = 288 cm
The circumference of circle Z is 288 cm.