Use the formula for the circumference of a circle:
\(\displaystyle{C}={2}π{r}\)

Let r be the radius of the original circle so that: \(\displaystyle{2}π{r}={48}π\)

\(\displaystyle{r}={48}

Let r be the radius of the original circle so that: \(\displaystyle{2}π{r}={48}π\)

\(\displaystyle{r}={48}