Abstract
TOPSIS is one of most popular methods in the process of selecting a possible course of action from all of the alternatives. In this paper by using the nearest weighted interval approximation of the fuzzy numbers we try to extend TOPSIS in fuzzy environment. This paper proposes four new fuzzy TOPSIS methods. Two numerical examples are given to clarify the main results developed in this paper. In these examples we have applied some non-triangular and non-trapezoidal fuzzy numbers too. These methods are evaluated and compared with some other existing methods. We can say that, this is the main advantages of the proposed methods, because, other fuzzy TOPSIS methods can't solve these kinds of problems.