We must find the arc of a circle with arc 30pi and 225 degrees.
For this, we can use the equation for the length of a circle which says that:

Where r is the radius of the circumference, however first we must find the length of the 360-degree arc of the circumference, for we do the following equality:

Now we clear C:

The length of the 360-degree arc of the circumference is 48pi, we replace this in the first equation and solve for the radius

In conclusion, the answer is that the radius measures 24