Help us caption and translate this video on Amara.org: http://www.amara.org/en/v/B2vw/ Esercizi: http://www.khanacademy.org/exercise/geometry_1 Traduzione in Italiano del video Area of a circle http://www.youtube.com/watch?feature=player_embedded&v=tCrDyJsSFok http://www.khanacademy.org/video/area-of-a-circle?playlist=Geometry Help us caption & translate this video! http://amara.org/v/B2vw/