Hmm....can you clarify what is 6 m long?
Does the length of a side of the base = 6 m ...or is the 6 m the length of the apothem?
Or does the 6 m stretch from corner to corner on the hexagon?
Or does the 6 m stretch from "wall" to "wall" on the hexagon?
If the length of one side of the base is 6m, then you have the correct answer.