Sphere is a solid figure bounded by a spherical surface or sphere, formed by rotating a circle about its diameter. The sphere is a rotating surface.
The distance from any point on the surface of the sphere to its center is called the radius of the sphere.
The diameter of a sphere is a straight line connecting any two points on the surface or sphere and passing through the center of the sphere. All diameters of a sphere are of equal length. The diameter is twice the radius.
$$S=4 \pi r^{2}=\pi d^{2}$$
where,
π— Pi or Archimedean constant is a mathematical constant that is the ratio of the circumference of a circle to its diameter; the approximate value of pi is 3.14159265359;
r— radius of the sphere;
d— diameter of the sphere.
The volume of a sphere is equal to one-third of the product of the sphere's surface area and its radius:
$$V=\frac{1}{3}\times S \times r=\frac{4}{3}\pi r^{3}$$