With the increase of Internet of Things (IoT) applications, indoor positioning systems have begun to gain importance. Since there is no widespread technique in this area like Global Positioning System (GPS) at outdoors, a vast variety of techniques and technologies are being used in indoor positioning. Triangulation is one of the most frequently used techniques which can be categorized into two techniques: lateration and angulation. Lateration technique uses distance information in the estimation of location while the angulation technique uses angles besides distances. The lateration technique is called as trilateration when it is applied in two dimensional space. In this paper, trilateration technique is analyzed where one of the reference points resides of an uncertain location. The location of an object is estimated as an area by using two certain reference points. The proposed method determines an added value which represents how much the area is reduced. Experiments are performed to calculate an approximate added value without applying the proposed method because of the costly calculation requirements. The results of the experiments and the obtained added values are also reported as final evaluation of the study.