1, the volume formula of the sphere: V=(4/3)πr3. 2. The "ancestral grave principle" developed independently by Zu Chongzhi and his son is richer than Archimedes' and involves more complicated issues. Zu Chongzhi and his son, Zuxuan, solved the problem of calculating the volume of the ball with ingenious methods. 3. In "Nine Chapters of Arithmetic", it is considered that the ratio of the circumscribed cylinder of a sphere to the volume of the sphere is equal to the ratio of the area of a square and its inscribed circle. Liu Hui, when commenting on Nine Chapters Arithmetic, pointed out that the statement in the original book was incorrect, only the ratio of the cover of a square (the volume of the common part of two vertically intersecting cylinders) to the volume of a sphere was exactly equal to the ratio of the area of a square and its inscribed circle. However, Liu Hui did not get the volume formula of the vertical intersection of two cylinders, so he could not get the spherical volume formula. Zu Chongzhi and his son used the principle that "two solids with the same cross-sectional area at the same height must have the same volume" to calculate the volume of "Mouhe Square Cover". The volume of the sphere is equal to π/4 times the volume of the "Mouhe Square Cover", so as to finally calculate the volume of the sphere. This formula is the famous "axiom of ancestor's declaration". 4. It is known that: (1/2)V sphere =(2/3)πr3, which is finally available, and V sphere =(4/3)πr3. The formula of sphere volume is derived from this.