<![CDATA[The purpose of this study is: To find out whether the application of Problem Based Learning Strategy (SPBM) can improve students' mathematical problem solving abilities on the subject of Spatial Geometry in Class XII Students of SMA Negeri 1 Siborongborong in the 2019/2020 Academic Year. The subjects in this study were Class XII students of SMA Negeri 1 Siborongborong for the academic year 2019/2020 with a total of 34 people. The object in this study is the students' mathematical problem solving ability during the implementation of learning through Problem Based Learning Strategies (SPBM) on the subject matter of Spatial Geometry in Class XII Students of SMA Negeri 1 Siborongborong for the 2019/2020 academic year. The instrument used is a test consisting of 5 questions. The test results after action I, classically obtained the level of problem solving ability of 82.40% with an average of 74.24 this shows that students' mathematical problem solving abilities have increased to the medium category. The average teacher activity in managing learning in the first cycle at the first meeting was 3.50 in the "good" category and the second meeting was 3.58 in the "very good" category. The results of the test in cycle II, obtained classically the level of problem solving ability of 88.20% with an average of 76.97 this shows that students' mathematical problem solving abilities have increased to the medium category. The average activity of teachers in managing learning in cycle I at the first meeting was 3.75 and was in the "very good" category. From the actions in cycle I and cycle II, it was concluded that the application of Problem-Based Learning Strategies (SPBM) could improve students' mathematical problem solving abilities on the subject of Spatial Geometry in Class XII Students of SMA Negeri 1 Siborongborong for the 2019/2020 academic year.]]>
