The text presents a circular function approach to trigonometry by demonstrating connections between the familiar algebra and the new language of trigonometry. This method—along with foreshadowing—is used throughout the text to provide students with a comfortable base for learning something new from something old or familiar. With just a few connections to algebra, students have the tools to understand the circular functions, their domains and ranges, and the relationship between the circular functions and the functional values. The approach immediately launches the student into the concept of periodic functions, their applications, graphs, and use in modeling many periodic phenomena. Beginning with this approach provides the student with a common thread that can be used to discover, connect and understand the remaining concepts of trigonometry.