Sphere Source: https://s1.static.brasilescola.uol.com.br/be/conteudo/images/potencial-no-interior-uma-esfera-eletrizada-5515a9675440a.jpg Let a point in space and r be a positive real number. The set of all points whose distance from O is less than or equal to r is called a sphere with center O and radius r. The spherical surface with center O and radius r is the set of points whose distance from point O is equal to r. We can imagine a spherical surface as the "shell" of a sphere, but a shell without thickness. Sphere volume Source: https://static.preparaenem.com/2021/06/esfera-centro-raio.jpg The volume of a sphere of radius r is given by: Sphere surface area: Source: https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRjpkATG9xgRAD2gH3NCncB8GQ2V_f7Wsm3mb3u0UUtUevH9rp7KfvWEpPOs3hieRBxAsM&usqp=CAU References: CHAVANTE, Eduardo; PRESTES, Diego. Mathematics 2. First Edition. São Paulo: Quadrant, 2016.