A solid sphere is a three-dimensional geometric shape that is perfectly round and has all points on its surface equidistant from its center. This distance is known as the radius. Solid spheres are commonly found in nature and everyday objects, such as balls and marbles. In mathematics, the volume of a solid sphere can be calculated using the formula V = \frac43 \pi r^3 , where r is the radius. The surface area can be determined with the formula A = 4 \pi r^2 . Solid spheres are important in various fields, including physics and engineering, for their unique properties.