This informal, readable text designed for use in a one-semsester course on right triangle trigonometry or trigonometric functions of angles, contains thorough emphasis on graphing techniques and graph reading, and an outstanding variety of exercises. A geometry appendix provides a review of plane geometry. Graping calculators are dealt with realistically with discussions of their uses and limitations. A graphing calculator supplement offers exercises and additional instructions. Optional Excursion sections give students interesting background information, applications, or deeper coverage of various topics.