The research aims to produce studentsâ worksheet validly and practically with Realistic Mathematic Education (RME) approach on the triangle lesson. This research was conducted at Junior High School 7 Bengkalis. The subject of this research are the experts and students class VII which 6 among them taken as small group trial and 30 students taken as big group trial. The development usedthe ADDIE method, namely: (A) analysis, including the curriculum analysis and the needs analysis; (D) design, including the preparation of studentsâ worksheet; (D) development, to develop studentsâ worksheet with Realistic Mathematics Education (RME); (I) implementation, in the small and big group; (E) evaluation, to analyze the data. The scores of results through the inquiry conducted by the media, the material, the small group trial, and the big group trialare90%,84,45%,90,08%, and 89,14% respectively. The data shows that the development of the studentsâ worksheet is appropriate and does not have to be revised, but needs to follow up on comments and suggestions to complete.