## Area of the surface

A circle located in the plain XOY have center in c(0,0,0) and radius $r>0$. Determine a parameter for the cylinder formed by all lines that are the circumference and are parallel to the vector $v=(3,0,4)$. Calculate the area of the surface thus obtained, located between plans $\pi 1: z=-4$ and $\pi 2: z=4$