Integrated teaching is a teaching orientation that assists students in developing the ability to synthesize knowledge, skills, and so on from a variety of fields to effectively solve problems in learning and in life, which is done right in the process of acquiring knowledge and practicing skills. This means that mathematical teaching establishes the relationship between different concepts of the same subject and different subjects, ensuring that students can mobilize their knowledge and capacity to solve problems. In other words, integrated teaching is a method of teaching in which knowledge is organized and solidified.  This study aims to propose integrated strategies for teaching the Geometric Sequence topic and illustrative examples. Furthermore, the study compares the effectiveness of integrated teaching to traditional teaching methods. This objective was achieved through a pedagogical experiment with a non-random and post-test-only control design. This study's sample population consists of 69 upper secondary school students in Can Tho City, Vietnam. The sample in this study was divided into two classes, one for the experimental class and one for the control class. Documentation, observation, written tests, interviews, and student worksheets will be used to gather the necessary data. The data was analyzed using the U-test. The study's finding shows that students' learning outcome in the experimental class is significantly higher than that of students in the control class. The study's findings confirm the feasibility of using integrated teaching to teach geometric sequence knowledge in high schools. It is suggested that more research is conducted on the use of integrated teaching methods in high schools.