<![CDATA[Mathematics plays an essential role in daily life, requires effective learning, participatory and supported by media that helps visualize abstract concepts. The Merdeka Curriculum encourages differentiated learning and provides teachers with the freedom to develop engaging learning media, including student worksheets. Integrating ethnomathematics such as the local culture of Sidoarjo into the student worksheets can make learning more meaningful. Students still experience difficulties in geometry, particularly in dilation, making the development of an ethnomathematics-based student worksheets highly relevant. This study is a Research and Development using the Dick and Carey development model, which consists of ten stages, from identifying learning objectives to conducting summative evaluations. The research subjects were 34 grade XI-1 students from MAN Sidoarjo. The study focuses on the process and results of developing an ethnomathematics-based student worksheets for grade XI that is valid, practical, and effective. Data collection techniques include interviews, observations, questionnaires, tests, and documentation, using instruments such as the Learning Objective Flow, teaching modules, student worksheets, quiz questions, teacher and student questionnaires, observation sheets, and validation sheets.The results show that the ethnomathematics-based student worksheets on dilation for grade XI is feasible for use. Validity scores reached 100% for the learning objective flow, teaching module, student questionnaire, and teacher questionnaire; the student worksheets 96%, the quiz 95%, and the observation sheet 100%. Practicality scores for student responses 92%, teacher responses at 100%, and observation sheets at 100%. The effectiveness of the student worksheets is demonstrated by learning mastery, with 97% of students successfully completing the quiz. Keywords: LKPD; Ethnomathematics; Sidoarjo; Dilation.]]>
