Mathematical Misconceptions of 7th Grade Students on Geometry Problem Using Three-tier Diagnostic Test

Abstract

This research aims to describe the mathematical misconceptions of 7th grade students on geometry problem base on three-tier diagnostic test. This research is descriptive qualitative research with 7th grade students of SMPN 17 Malang as research subjects who have been taught the geometry problem especially concept of lines and angels. The results showed that students experienced 4 misconceptions related to lines and angles, namely: 1) misconceptions about naming points, lines, and planes; 2) misconceptions about the definition of the position of two lines, namely lines that are parallel, intersecting, and perpendicular; 3) misconceptions about the definition of an angle based on the size of the angle, namely right angles and obtuse angles; 4) misconceptions about the effect of two parallel lines cut by a transverse line, namely opposite angles and complementary angles. The causes of these misconceptions include: 1) intuitive thinking, 2) concluding errors, 3) less than optimal online learning, 4) students' lack of interest in learning, 5) image reasoning errors, 6) teacher's lack of emphasis on mathematical concepts, and 7) simplification of the concept.