The geometry ability of junior high school students in Karanganyar based on the Hoffer’s theory

Abstract

Geometry ability is the aspect which underlay students to solve the geometry problems. However, some studies suggests the difficulty students when learning geometry. This leads to the ability of the geometri students difficult to develop. There are five the geometry ability based the Hoffer’s theory, namely visual, verbal, drawing, logical, and applied. These five aspects are basic geometry ability to be mastered by Junior High School students level. This study aimed to describe the students’ geometry ability according to the Hoffer’s theory. The participants of this study are six students from 9th grade in State Junior High School 1 Jaten at Karanganyar that consisted of three categories, namely higher ability, moderate ability, and lower ability students. The data collection methods used are geometry test and in-depth interview and than analyzed using triangulation. The result of the study showed that the ability of those three categories is different. Each of the students' geometry ability can be described as follows. (1) On visual skill, higher ability and moderate ability students could mention the elements of the geometrical shapes correctly based on its shapes obtained. However, lower ability students were unable to mention it specifically; (2) On verbal skill, moderate ability students were able to link the relationship among shapes based on the characteristics correctly, despite that the higher ability and lower ability seemed to have difficulty; (3) On drawing skill, higher ability students could construct the shapes based on the relationship among shapes well, but moderate ability and lower ability students continually faced difficulty; (4) On logical skill, both higher ability, and moderate ability students were able to determine the formula of a particular geometrical shape based on the relationship among the elements of the shape well, while the lower ability students were unable to; (5) On applied skill, higher ability, and moderate ability students could apply the concept of geometry into the problem-solving question, but seemed to have difficulty with the calculation. Besides that, lower ability students could not ultimately implement the concept of geometry.