According to the general education curriculum in Mathematics 2018, mathematical thinking and reasoning capacity is one of five essential components of mathematical competence. The ability to use analysis and synthesis in problem-solving is a crucial component of mathematical reasoning and thinking capacity. The topic of perpendicular relations in space is an essential group of knowledge in the program, with many opportunities and conditions for developing mathematical thinking and reasoning abilities for students. In this article, we introduce the teaching process used to train students in analysis and synthesis while teaching math problems on the topic of perpendicular relations in space, thereby contributing to the development of students’ mathematical thinking and reasoning ability