Welcome to Trigonometry Workbook, Volume I: Conversion of Angle Units . This book is designed to help students, educators, and self-learners develop a strong understanding of one of the most essential skills in trigonometry: converting between different units of angle measurement. Angles can be expressed in degrees, radians, and sometimes gradians (it is omitted in this book). Mastering the conversion between degrees and radians is a fundamental requirement for success in higher-level mathematics, physics, engineering, and various applied sciences. However, many learners find these conversions confusing when first introduced. This workbook aims to eliminate that confusion by offering clear explanations, step-by-step examples, and comprehensive practice exercises with fully worked-out solutions. What makes this book different? Each problem is crafted to reinforce conceptual understanding and accuracy. Solutions are detailed, leaving no step unexplained, ensuring you build confidence with every exercise. Whether you are preparing for exams, teaching in the classroom, or reviewing for personal growth, this workbook will serve as a practical guide to mastering angle unit conversions. By the end of this book, you will know how to convert between degrees and radians. Let’s begin this journey toward mastering trigonometry—one angle at a time.