Answer:
Increased by a factor of 4
Explanation:
The original circumference is:
 C1 = 2 * pi * r1
 The new circumference is:
 C2 = (2 * pi * r2)
 "circumference that is 4 times larger than the original"
 (2 * pi * r2) = 4 (2 * pi * r1)
 Rewriting:
 r2 = 4r1
 Answer:
The radius of the original circle is:
 increased by a factor of 4
Hope this helps :)