Influence of Problem Based Learning Model on Students’ Mathematical Reasoning Ability

 The study aimed to determine the effect of problem-based learning models on students' mathematical reasoning abilities. The study used an experimental method with a quasi-experimental design and a posttest-only control design. The population was all classes in VIII grade at MTs Negeri 3 Mempawah in the 2019/2020 school year. The samples were students of VIII C and VIII A grades and were drawn using simple random sampling. Data collection techniques and tools were measurements that used a essay test contained indicators of mathematical reasoning abilities. After being tested in the two samples, data analysis was then carried out to test the hypothesis. Before testing the hypothesis, first, a prerequisite test was carried out, namely the normality test. Because the data are normally distributed, to test  the hypothesis we used the t-test. It was obtained that tcount = 11.15 and ttable = 1.99 with α = 0.05. Because of the value of tcount> ttable, it can be concluded that the problem-based learning model affects students' mathematical reasoning abilities. Keywords: Problem based Learning, Mathematic, Reasoning Ability