The objective of this research was to analyze the construction of mathematical knowledge associated with the linear inequalities that Chilean students carried out through graphic argumentation, in a modeling process framed in the Socioepistemological Theory of Educational Mathematics. To fulfill this objective, the methodology was qualitative and consisted of a case study in which 28 Chilean 12th grade students participated in a classroom situation where a modeling process was applied through the use of a mobile phone application called Sound Analyzer that designs graphs of a sound in decibels according to time. The students described the number of decibels of a certain song and identified the time intervals in which that song exceeded the number of decibels established by regulation by the Ministry of the Environment of Chile. As a result of the investigation, it was found that the students were able to generate, in a modeling process and through graphic argumentation, a resignification of mathematical knowledge associated with linear inequalities.