Trigonometry: From Theory to Application offers a clear and practical introduction to the foundational principles of trigonometry, guiding readers through the subject with an emphasis on real-world relevance. The book thoughtfully explores the characterization of triangles, coordinate transport, and coordinate systems, providing straightforward explanations and practical insights. Beginning with an accessible review of basic trigonometric functions and their properties, the text gradually expands to cover identities, equations, and a broad range of applications. Each chapter builds on the last, ensuring that learners develop a strong, cumulative grasp of the material through detailed examples and engaging exercises. In addition to its comprehensive approach, the book features special sections devoted to real-life and technological problems, illustrating how trigonometry is not just a theoretical subject but a vital tool in solving everyday challenges. Full-color illustrations and a variety of exercises help students connect concepts to applications in fields like engineering and physics, making the subject both inspiring and relevant. This integrated approach motivates learners to appreciate the significance of trigonometry beyond the classroom environment.