The number [tex]\pi[/tex] is defined exactly as the ratio betweent the circumference and the diameter. We deduce that
[tex]\pi=\dfrac{C}{d}\iff C=\pi d[/tex]
So, your cimference is [tex]2\pi[/tex]. You can use the approximation [tex]\pi=3.14[/tex] to round to the nearest hundredreth: [tex]2\pi\approx 6.28[/tex]
