Ethnomathematics in Creating Tanjak from Tanjungpinang

Several preliminary studies have found the importance and promising effect of ethnomathematics in mathematics education. Therefore, this research aims to identify and describe the ethnomathematics in creating Malay male headgear called tanjak. This ethnography research collects data from local creators tanjak in Tanjungpinang, Riau Archipelagic Province through observation, interview, and document. The data collected were processed through reduction, presentation, and drawing conclusions. The results showed that some types of mathematical activities, such as creating rectangular and triangular shape, halving plane area, plane symmetry, measuring the length using standard and non-standard units, and generating a relationship between the length of cloth and predicted of an average person's head circumference are used to create tanjak.