Answer: 
Step-by-step explanation:
In the given figure we have given a circle in with radius PC = 18 inches
Also, the central angle made by arc AC
or 
Since the sum of angles at a point is 
Then , the central angle made by arc AC :-

The formula to find the arc length is given by :-

Then the length of arc ABC will be :-

Hence, the length of arc ABC = 