Incorrect. To find the circumference, you substitute in $\displaystyle{3}{y}\usepackage{cmbright}\Huge\$ for r in the formula $\displaystyle{C}={2}\pi{r}\usepackage{cmbright}\Huge\$ . This gives you $\displaystyle{C}={2}\pi{\left({3}{y}\right)}\usepackage{cmbright}\Huge\$ . Can you simplify this expression?