Respuesta :

[tex]3\pi d=12\pi\ \ \ \ |divide\ both\ sides\ by\ 3\\\\\pi d=4\pi\ \ \ \ |divide\ both\ sides\ by\ \pi\\\\\huge\boxed{d=4}[/tex]
[tex]\sf 3\pi d = 12\pi \\ \\ (3)(3.141593)d = (12 ) (3.141593) \\ \\ Simplify \ both \ sides \ of \ the \ equation. \\ \\ 9.424778d = 37.699112 \\ \\ \ Divide \ both \ sides \ by \ 9.424778 \\ \\ 9.424778d/ 9.424778 = 37.699112/ 9.424778 \\ \\ \bold{\boxed{d = 4}}[/tex]