Answer
Circle in the vertical plane $(x=7)$ of radius $12$ centered at the $(7,0,0)$.
Work Step by Step
We put
$$ x=7,\quad y=12\cos t, \quad z=12\sin t $$
hence we get
$$ y^2+z^2=144\sin^2t+144\cos^2t=144.$$
Which is a circle in the vertical plane $(x=7)$ of raduis $12$ centered at the $(7,0,0)$.
