We are given the following diagram and we want to find its circumference.
The circumference $C$ of a circle with diameter $d$ is calculated using the formula below.
\begin{gathered}
C=\pi d
\end{gathered}
From the diagram, we know that the diameter of the circle is $\colIII{20\text{ centimeters}}.$ By substituting $20$ for $d$ in the formula, we can calculate $C.$
