ANALYSIS OF STUDENTS’ ERRORS IN SOLVING CIRCLE GEOMETRY PROBLEMS

Abstract

This study aimed to identify the types of errors made by Grade 11 students when solving circle-geometry problems and to explore factors associated with those errors using Newman’s Error Analysis Procedure. Descriptive qualitative design was employed. Six students at SMA GKST 1 Tentena, Poso Regency, Central Sulawesi, were purposively selected to represent high, moderate, and low mathematical ability. Data was collected through a written test consisting of three open-ended problems on inscribed angles, circle circumference, and the equation of a circle, followed by task-based interviews and documentation. The data were analyzed through data condensation, data display, and conclusion drawing and verification, with students’ responses classified into Newman’s five error categories. Across 18 student-problem responses, process-skill errors occurred most frequently (9 cases; 50.0%), followed by comprehension errors (6; 33.3%), transformation errors (6; 33.3%), encoding errors (5; 27.8%), and reading errors (1; 5.6%). Because one response could contain more than one error category, percentages are calculated separately for each category using 18 responses as the denominator and are not intended to sum to 100%. The findings point to a need for instruction that combines conceptual explanation, explicit mathematical representation, procedural checking, and complete written conclusions.