[tex]\bf \textit{distance around the crater, or Circumference of a circle}
\\\\\\
C=2\pi r\qquad
\begin{cases}
C= circumference\\
r=radius=\frac{diameter}{2}\\
--------------\\
diameter=3400\\
r=\frac{3400}{2}
\end{cases}
\\\\\\
C=2\pi \cdot \frac{3400}{2}[/tex]
