You're given an angle, the side adjacent to the angle, and are looking for the hypotenuse.
Use cosine = adjacent / hypotenuse.
cos(60) = 2√(3) / x
Rearrange the equation to solve for x (multiply both sides by x, then divide both sides by cos(60)).
x = (2√(3)) / (cos(60))
x equates to about 6.928
