Incorrect. The quarter has a diameter of about 24 millimeters. Divide this value in half to find the radius of the quarter: $\displaystyle\frac{{24}}{{2}}={12}\usepackage{cmbright}\Huge\$ millimeters. Use $\displaystyle{r}={12}\usepackage{cmbright}\Huge\$ in the formula $\displaystyle{A}=\pi{{r}}^{{2}}\usepackage{cmbright}\Huge\$ to find the area of one side of the quarter.