Variance of Bernoulli Distribution/Proof 3

Theorem
Let $X$ be a discrete random variable with the Bernoulli distribution with parameter $p$.

Then the variance of $X$ is given by:
 * $\operatorname{var} X = p \left({1 - p}\right)$

Proof 3
We can simply use the Variance of Binomial Distribution, putting $n = 1$.