S: a S b ⟺ a ≥ b

Since a=a ∀a ∈ R, therefore a ≥ a always. Hence (a, a) always belongs to S ∀a ∈ R. Therefore, S is reflexive.

If a ≥ b then b ≤ a ⇏ b ≥ a. Hence if (a, b) belongs to S, then (b, a) does not always belongs to S. Hence S is not symmetric.

If a ≥ b and b ≥ c, therefore a ≥ c. Hence if (a, b) and (b, c) belongs to S, then (a, c) will belong to S ∀a, b, c∈R. Hence, S is transitive.