We know that the area of a circle is:
[tex]A=\pi r^2[/tex]
If pi is equal to 3.14 then we can find the radius of the circle so:
[tex]\begin{gathered} 530.93=3.14r^2 \\ \frac{530.93}{3.14}=r^2 \\ 169=r^2 \\ \sqrt[]{169}=r \\ 13=r \end{gathered}[/tex]
now with the radus wwe can calculate the circunference so:
[tex]\begin{gathered} C=2\pi r \\ C=2\cdot3.14\cdot13 \\ C=81.68 \end{gathered}[/tex]
