This booklet is the third in a series of nine from the Teacher Training Institute at Hofstra University (New York) and includes 11 samples of computer program lessons designed to enhance the teaching of secondary school mathematics. An introductory section includes the purpose and rationale for this series of software programs, the role of the computer in school mathematics, and contact information for availability of programs. An outline of the specific topic, the description of the program sequence, the required mathematical background, the program uses, the suggested homework assignments, and a pedagogical commentary are included for each of the following program topics: (1) the sine relationship in the first quadrant; (2) the cosine relationship in the first quadrant; (3) the sine and cosine relationships in all quadrants; (4) the linear combination of sines and cosines; (5) the inverse of a parabola; (6) the inverse of the sine function; (7) the straight line; (8) the upright parabola; (9) more graphs of parabolas; (10) the absolute value function and its graph; and (11) general parameters for graphing functions. (JJK)