Here's how to find the length of side AB:
Since triangle ABC is equilateral, all its sides are equal, and all its angles are 60 degrees. The radius of the circumcircle is given as $$4\sqrt{3}$$.
We can use the formula relating the side of an equilateral triangle to the radius of its circumcircle:
$$R = \frac{a}{ \sqrt{3}}$$
where R is the radius of the circumcircle and a is the side of the equilateral triangle.
We are given $$R = 4\sqrt{3}$$. We need to find 'a'.
$$4\sqrt{3} = \frac{a}{\sqrt{3}}$$
Multiply both sides by $$\sqrt{3}$$:
$$a = 4\sqrt{3} \cdot \sqrt{3} = 4 \cdot 3 = 12$$
So, the length of side AB is 12.
Answer: 12