Help us caption and translate this video on Amara.org: http://www.amara.org/en/v/B2wG/ Esercizi: http://www.khanacademy.org/exercise/equation_of_a_circle_1 Traduzione in Italiano del video Conic Sections: Intro to Circles http://www.youtube.com/watch?v=6r1GQCxyMKI http://www.khanacademy.org/video/conic-sections--intro-to-circles?playlist=Algebra Help us caption & translate this video! http://amara.org/v/B2wG/