Volume 2 : 3 ratio of the volumes of the sphere and cylinder is credited to Archimedes. The volume of a sphere is the integral of an infinite number of infinitesimally small circular disks of thickness "dx". The calculation for the volume of a sphere with center 0 and radius "r" is as follows. The surface area of the circular disk is formula_10. The radius of the circular disks, defined such that the x-axis cuts perpendicularly through them, is or where y or z can be taken to represent the radius of a disk at a particular x value. Using y
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