Question

The circle shown here has area πr2. If its radius is tripled in length its new area will be

Answer 1

`\bf \textit{area of a circle}\\\\ A=\boxed{\pi r^2}~~ \begin{cases} r=radius\\ -----\\ r=\stackrel{tripled}{3r} \end{cases}\implies A=\pi (3r)^2\implies A=\pi (3^2r^2) \\\\\\ A=9\boxed{\pi r^2}\impliedby \textit{9 times the original area}`