Use the links for more practice.
http://www.khanacademy.org/math/algebra/linear-equations-and-inequalitie/more-analytic-geometry/v/distance-formula
http://www.brightstorm.com/math/trigonometry/pythagorean-theorem/distance-formula/
Homework: I will collected both WS 4.4 (both sides) and your last page of the notes (had the book problems attached).