These three pieces are hung as a group and their center is at 57". Additionally, when hanging a "gallery wall," better balance if found when larger/heavier pieces are hung on the left, not the center or the right side (as seen here with the largest piece on the left).
I have always loved artwork and thought that it was the most most personal part of any home, but I never knew how to make it all look good on the wall.
Then a friend gave me a great tip that to THIS day has made picture hanging a simple, gratifying task. The tip? Always hang your artwork at 57" on center. Confused? "On center" means that the middle of the artwork is always at 57" (obviously, the hook will be higher). Interestingly, the 57" standard represents the average human eye-height and is regularly used as a standard in many galleries and museums.