Area of a Sector

Pac-Man is going through his daily routine: eating Pac-Dots, avoiding ghosts, and the like. To eat a Pac-Dot, Pac-Man needs to open his mouth super wide (about a quarter of his body!) and chomp down as hard as he can (making his mouth about a tenth of his body). If Pac-Man has radius $p$, what is the change in angle of the two sectors formed by Pac-Man's open and closed mouth?