Arithmetic Sequence at Gorga

This research examines the process of making traditional Batak ornaments called gorga. The process will be analyzed mathematical concepts used in making gorga. Based on observations, one of the concepts used in making gorga is arithmetic sequence. This research is aimed at describing the modeling process carried out by engravers using local wisdom (emic) and relating it to academic mathematical modeling (etic). This research involved five gorga carvers in Tobasa and Samosir areas. Data was collected through direct observation, as well as interviews with gorga sculptors. The results showed the existence of arithmetic sequence concepts in the process of making gorga.