Hi I really need help on this problem. Thank you!

Answer:
The circumference of a circle with radius 13.8 is 86.71
Step-by-step explanation:
Circumference of a cicle in terms of radius:
Circumference = 2·π·r = 2·3.14·13.8 = 86.71
In terms of diameter:
Circumference = π·d = 3.14·27.6 = 86.66
In terms of area:
Circumference C = √4·π·A = √4·π·598.3 = 86.71