Solve
-Find the Lateral (Side) Surface Area of the Cone $y = x / 2,0 \leq x \leq 6$

Multiple Choice

Solve.
-Find the lateral (side) surface area of the cone generated by revolving the line segment $y = x / 2,0 \leq x \leq 6$ , about the $x$ -axis.

A) $3 \pi \sqrt { 7 }$
B) $9 \pi \sqrt { 7 }$
C) $3 \pi \sqrt { 5 }$
D) $9 \pi \sqrt { 5 }$