Answer:
15 cm.
Explanation:
Recall that the arc-length of a circle is given by the formula:

Where r is the radius and θ is the measure of the central angle in radians.
The circle has a diameter of 24 cm, so its radius is 12 cm.
And its central angle is 1.25 radians. Hence, the arc-length will be:

In conclusion, the arc-length for a circle with a diameter of 24 cm subtended by a central angle of 1.25 radians is 15 cm.