Digital learning platforms can be excellent supplements. While not an official answer key, sites like contain user-created flashcards and study sets for "Music in Theory and Practice, Volume II." For example, Quizlet offers "resources containing chapter practice answers and detailed information on the problem-solving process". These can be incredibly useful for drilling key terms, chord identifications, and other factual recall, providing a form of immediate feedback. Similarly, platforms like Course Hero allow students to share study resources, though you should always verify their accuracy against your coursework.
Be mindful of the terms of service for these platforms regarding copyrighted textbook material. Tips for Using the Answer Key Effectively music in theory and practice volume 2 answer key pdf