PENGUASAAN KONSEP LINGKARAN TERHADAP KEMAMPUAN SPASIAL MATEMATIKA SISWA POKOK BAHASAN BANGUN RUANG SISI LENGKUNG KELAS VIII SMP NEGERI 1 KOTA CIREBON

The concept of circle is a basic concept that must be understood for students to learn about curved side three dimentional figure. The connection of concept of circle to learn curved side three dimentional figure can improve students’ spatial ability. This research was aimed to 1) determine mastery of the concept of the circle class VIII SMP Negeri 1 Cirebon City; 2) determine the ability of spatial math students; 3) determine whether there is influence mastery of the concept of the circle to the spatial abilities of students in the subject of mathematics with curved side three dimentional figure. This research was conducted in SMP Negeri 1 Cirebon, population was 359 students of class VIII students. Sampling was done by cluster random sampling, 38 students class VIII D were as research sample. Based on data analysis, the results showed that the average value of the circle concept mastery tests was 70.34 and a high category average of 72.34 spatial ability tests including high category. The regression equation to predict the spatial abilities of students based on mastery of mathematical concepts circle is 𝑦 = 31.29 + 0,58x, this indicated a positive effect. After testing the hypothesis with  = 0.05, the analysis shows that there is influence of mastery of the concept of the circle to the spatial abilities of student mathematics subjects with curved side three dimentional figure with a contribution of 42% and 58% was determined by other factors.