Use the links for more practice.
https://www.youtube.com/watch?v=ZSykEIJQSVs
https://www.youtube.com/watch?v=ASFHlTgdNkE
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/
HW: WS 4.4 (not 4- 6, nor 10 - 12)