The cricumference formula is given by:
where C denote the circumference, d the diameter of the circle and Pi is the constant equal to 3.14.
Case 1.
In this case, d=5.5 cm, then by substituting this value into the formula, we get
Case 2.
Now, by substitutinfg d=8m, into the circumference formula, we get
Case 3.
Finally, by substituting d=5.8m into the formula, we obtain
In summary, the answers are: