Step-by-step explanation:
a diameter is always twice the radius.
the only pairs I can see in the list, where one number is twice the other :
2.5 and 5
7.6 and 15.2
so,
2.5 is the radius of A
5 is the diameter of A
7.6 is the radius of B
15.2 is the diameter of B
15.7 is then the circumference of A (as the smaller of the remaining 2 numbers)
47.7 is the circumference of B
we can also check via the formula for circle circumference :
c = 2×pi×r
and yes, the rounded c for r=2.5 is 15.7, and for r=7.6 is 47.7
