The Method of Mechanical Theorems convenient to use a little bit of coordinate geometry. If a sphere of radius 1 is placed with its center at "x" = 1, the vertical cross sectional radius formula_2 at any "x" between 0 and 2 is given by the following formula: The mass of this cross section, for purposes of balancing on a lever, is proportional to the area: Archimedes then considered rotating the triangular region between "y" = 0 and "y" = "x" and "x" = "2" on the "x"-"y" plane around the "x"-axis, to form a cone. The cross section of this cone is a circle
The X Factor (Greece series 4) of boot camp, the 80 acts were reduced to 32. After an emotional "Four Chair Challenge", the 32 acts were reduced to 16, who went on to the live finals, with one act being eliminated each week by a combination of public vote and judges' decision until a winner was found. There was an exception for the first live show, where four acts, one from each category, were eliminated. The final 16 acts were confirmed as follows: Key; Key: The X Factor (Greece series 4) The fourth series of the music talent show The X Factor Greece began airing on