[tex]r\approx3.18cm[/tex]
1) Let's begin by reminding ourselves of the formula of the Circumference:
[tex]C=2\pi r[/tex]
2) Note that for this question, we'll round π as simply 3.14 so let's plug it into that formula with the Circumference:
[tex]\begin{gathered} 20=2(3.14)r \\ 2\mleft(3.14\mright)r=20 \\ 6.28r=20 \\ \frac{6.28r}{6.28}=\frac{20}{6.28} \\ r\approx3.18cm \end{gathered}[/tex]
Thus, this is the answer.
