Misconceptions of student junior high school in Solving Pythagorean Theorem

The learning process in the classroom is said to be successful, if most students understand the concepts conveyed by the teacher. But, in the learning process, teacher found stundents has misconception. Misconceptions gotten by students, will affect students in the use of a concept between concepts in the mathematic. Identification misconception is one way to learning process get successful. The purpose of this research was for describe the misconception and the solution of student’s misconception of class IX Junior High School 2 Sedati Sidoarjo at the solve the problem of Pythagorean Theorem. The qualitative research was used as form of this research, with the type of case study research. The data collection technique which was used were 1) Test methods, 2) interview method. The technique of data validation uses triangulation of method, by comparing test result data and interview. The results of this research can be showed as there were three types of misconceptions experienced by students that was classificational misconceptions, Correlational misconception, and Teoritical misconception; (1) students take types correlational misconception. The indicator is writing units incorrectly. Before learning about concept Pythagoras Theorem, students master about unit concept.; (2) students take types classification misconception. The indicator is students missing determine side figure two and three dimentional to Pythagoras Theorem. In this misconception, students difficult illustration skew right triangle.; (3) students take types teoritic misconceptioan. The indicator is students missing giving the reason of problem. In this misconception is about triple Pythagoras concept. Student determine triple Pythagoras with calculate not with concept giving as multiples or formulas. By knowing the description of misconceptions that occur in students, teachers take the steps of the learning process accurately so student do not misconception