[tex]\textit{lateral area of a cone}\\\\ LA=\pi r\sqrt{r^2+h^2}~~ \begin{cases} r=radius\\ h=height\\[-0.5em] \hrulefill\\ r=4\\ h=3 \end{cases}\implies \begin{array}{llll} LA=\pi (4)\sqrt{(4)^2+(3)^2} \\\\\\ LA=4\pi \sqrt{25}\implies LA=4\pi (5) \\\\\\ LA=20\pi \end{array}[/tex]
