Lopi Sandeq Construction Ethnomathematics: Analysis of Geometry and Numeracy System of the Mandar Culture

Abstract

Standard mathematics education often overlooks the rich mathematical concepts embedded in local culturres, leading to a gap between formal learning and indigenous knowledge. This study eksplores the ethnomathematical element ini the construction of the traditional Mandar boat, Lopi sandeq, which relies on intuitive mathematical principles. Using an ethnographic approach, data were collected through observation, documentation, and in-depth interviews with Punggawa in  Karama Village, Polewali Mandar. Data analysis employed mathematical abstraction to transform local knowledge into formal concepts. The findings reveal that geometric integration occurs within  its main components: the triangular priciple on the sail (Sobal), a parabolic curve on  the hull for hydrodynamic efficiency,  and bilateral symmetry  in the equilibrium system of Baratang and Palatto’. Additionally, the traditional numeracy system  based on depa units (dappa) consistently applies specific dimension ratios tailored to  the boat’s function (fisherman vs competition). This study concludes that Lopi Sandeq serves as  a living mathematics laboratory with great potential for integration into the independent Curriculum (Kurikulum Merdeka) as a  concrete, Culture-based learning medium.