Learning Geometry and The Value of Life from The Arts: Ethnomathematics on The Gamelan Reyog Ponorogo

Abstract

Many people still believe that mathematics is unrelated to human existence. However, mathematics is, in reality, inextricably linked to human culture and life. For example, Ponorogo, one of Indonesia's cities, is known for its culture and art, particularly Reyog Ponorogo. Therefore, mathematical principles that bring mathematics closer to human life can be investigated using existing civilizations. Furthermore, culture can be used as a basis for math education in schools. Thus, this study seeks to investigate geometric concepts and the value of life in gamelan Reyog Ponorogo. The research question is, what are the values and concepts of geometry in Gamelan Reyog Ponorogo?. This research is ethnography research. To gain a better understanding of the philosophical values inherent in each gamelan instrument Reyog Ponorogo, data is collected through observations, literature reviews, and interviews with Ponorogo elders.  The results showed that Gamelan Reyog Ponorogo uses the concept of geometry (field geometry, spatial geometry, transformation geometry, angular concepts, and the concept of two parallel lines cut by a line). In addition, each gamelan instrument Reyog Ponorogo contains traditional values, such as self-control, accountability, self-improvement, and so on. Therefore, it can be concluded that the gamelan Reyog Ponorogo is full of geometry concepts and the value of life.