Non-Closed Set of Real Numbers is not Compact/Proof 2

Theorem
Let $\R$ be the set of real numbers considered as a Euclidean space.

Let $S \subseteq \R$ be non-closed in $\R$.

Then $S$ is not a compact subspace of $\R$.

Proof
From: the result follows by the rule of transposition.
 * Real Number Line is Metric Space
 * Metric Space is Hausdorff
 * Compact Subspace of Hausdorff Space is Closed