Abstract :
The background of this research is less participation the student in learning process so the students ability reasoning not trained. It has impact for low the students achievement. One of learning model that emphasize the students active in the learning is cooperative learning model STAD type. Learning model cooperative STAD type is a learning model of agglomerate the students in the groups of 4-5 members heterogeneously and emphasized the activity and interaction among students to motivate each other and help each other to mastery the lesson in order to achieve the goal of learning process.. Purpose from this research to know the effect of learning model cooperative STAD type for the students learning achieviement of mathematic and the implementation of this model in learning mathematics by students class VIII at SMPK ST. Theresia Kupang in academic year 2016/2017. This research is quantitative research design in which pre-experimental method where the technique sampling used nonprobability sampling especially purposive sampling so the sample of this research is class VIII C. Based on the result of analysis using SPSS version 22 of the table paired samples test get the significan 0,000 with and tcal= 18,205 with ttable = 2,045. The result of analysis show that the significan = 0,000 < 0,05 = and tcal = 18,205 > 2,045 = ttable. So, Ha was acceptable and it can be concluded that there is a significant effect for students achievement by using learning model cooperative type STAD in teaching material tangent to the circle for students class VIII at SMPK St. Theresia Kupang in academic year 2016/2017. Based on the conclusion, the writer suggestion that the mathematics teachers can use and apply learning model cooperative type STAD especially for teaching material tangent to the circle.