Answer:
249.42 units²
Explanation:
Given only the apothem of an n-sided regular polygon, the area can be computed as ...
... A = n·a²·tan(180°/n)
For n=3 and a=4√3, this is ...
... A = 3·(4√3)²·tan(60°)
... A = 3·48·√3 = 144√3 . . . . units²
... A ≈ 249.42 units²