11.28π mm
1) Since the area is 100 mm² we can plug into the Circumference formula to find out the perimeter of that circle
2)
[tex]\begin{gathered} C=2\pi\cdot r \\ C=2\cdot\pi\cdot(5.64)^{} \\ C=11.28\pi \end{gathered}[/tex]3) Hence, the circumference of that circle is 11.28π mm
