A study determined the effect of college-level trigonometry skills on the final grades of students enrolled in Introduction to AC/DC Circuits, the first course in the vocational electronics program at Seminole Community College (Florida). The literature was reviewed to develop a conceptual framework for the project. A pretest that measured college-level trigonometry skills was administered to each student enrolled in all sections of the course at the beginning of the Spring 1990 term. Results were used to categorize students as those with college-level trigonometry skills (control group, N=11) and those without (experimental group, N=14). At the end of the term, final grades for each group were averaged and a statistical comparison of the mean scores for both groups was performed. Since the researchers believed the control group would score higher, a two-tailed independent t-test was used. The difference between the mean scores of the control group and the experimental group was statistically significant at the .01 level. It was recommended that the college should require a prerequisite of college-level trigonometry and modify participation in the program and that vocational faculty should teach the trigonometry skills applicable to AC circuits. (Fifteen references and an organizational chart for Vocational-Technical Education at Seminole Community College are appended.) (YLB)