Question 446745
The circumference is the diameter times pi.  The diameter is twice the radius.  If the circumference is 4sqrt3pi, then the diameter is 4sqrt3.  That makes the radius half the diameter-2sqrt3.
The area is the radius squared times pi.  So if the area is 4/9pi, then the radius squared is 4/9.  Then take the sqrt is 4/9 to get the radius. That's 2/3.
If the area is 49 pi, then the radius squared is 49. Then the radius is the sqrt of 49 which is 7.  So the radius is 7.  The circumference the twice the radius times pi.  So the circumference is 14pi.