[tex]\bf \textit{area of a circular ring}\\\\ A=\pi (R^2-r^2)~~ \begin{cases} R=larger\\ \qquad radius\\ r=smaller\\ \qquad radius\\[-0.5em] \hrulefill\\ R=12\\ r=7 \end{cases}\implies A=\pi (12^2-7^2) \implies A=95\pi[/tex]
