Mathematical reasoning through the application of solid geometry

Abstract

This study aims to find out how the process and results of students' reasoning abilities are faced with the problems of applying solid geometry. This research was conducted on 10 students of class VIII SMP in the even semester of the 2018/2019 school year. Data collection techniques using purposive sampling. Data triangulation process is carried out to confirm the results of the test and interview. The results of this study indicate that students' mathematical reasoning abilities measured by reasoning indicators have different results. Indicator of the ability to present mathematical statements verbally, in writing, drawings, diagrams, get good results because students have been able to write the information requested and find solutions to problems. Indicator of the ability to do mathematical manipulation to get enough results, because students in the process of working on mathematical manipulation are incomplete and inaccurate. Indicators compile evidence and give reasons to get bad results because students cannot give reasons precisely because the preparation of evidence is incomplete. The indicator draws conclusions from a statement getting bad results because students cannot deduce the questions given correctly due to a lack of understanding. Based on the results it was concluded that the student's reasoning ability was still lacking at the stage of giving reasons for the evidence compiled and inferring from a statement.