if the diameter is 7 units, the radius is half that, or 3.5
[tex]\bf \textit{area of a circle}\\\\
A=\pi r^2\qquad \boxed{r=3.5}\qquad A=3.5^2\pi \implies A=12.25\pi
\\\\\\
\textit{circumference of a circle}\\\\
C=2\pi r\qquad \boxed{r=3.5}\qquad C=2\pi 3.5\implies C=7\pi [/tex]
