In a college course, the final grade is determined by the following components: homework ($20\%$), quizzes ($30\%$), a midterm exam ($25\%$), and a final exam ($25\%$). If a student scored $90\%$ on homework, $85\%$ on quizzes, $70\%$ on the midterm, and $92\%$ on the final exam, what is their overall percentage grade in the course?