To determine if $x - 6$ is a factor of the polynomial function $f(x) = x^3 - 216$ using the Factor Theorem, evaluate the function at the corresponding value of $c$. For the binomial $x - 6$, the value is $c = 6$. Substitute $x = 6$ into the function: $f(6) = 6^3 - 216$. Evaluate the exponent to obtain $f(6) = 216 - 216$, which simplifies to $f(6) = 0$. Because the function evaluates to $0$, the Factor Theorem confirms that $x - 6$ is a factor of $f(x) = x^3 - 216$.