Triangular Fuzzy Number (TFN) is frequently used to represent fuzzy concepts in many applications. The advantages of applying TFNs include the simplicity of associative calculations, instinct interpretation of values, satisfaction of error-free reconstruction, and so on. In the first part of this study, two TFN-like LR-type fuzzy numbers, including the Truncated Triangular Fuzzy Number (TTFN) and the Generalized Triangular Fuzzy Number (GTFN) are introduced. Next, the concept of a TFN-driven system is defined, and the approximation of fuzzy parameters in such a system is investigated. Four approaches including Alpha Cut Tabling (ACT), Triangular Fuzzy Number Approximation (TFNA), Generalized Triangular Fuzzy Number Approximation (GTFNA), and Polynomial Fitting (PF) are proposed for achieving this purpose. Demonstrative examples are given. Advantages and disadvantages of each method are also discussed.