A sphere is a perfectly round three-dimensional shape where every point on its surface is the same distance from its center. This distance is known as the radius. Common examples of spheres include basketballs, bubbles, and planets like Earth. In mathematics, the volume and surface area of a sphere can be calculated using specific formulas. The volume is given by the formula \frac43 \pi r^3 , while the surface area is calculated using 4 \pi r^2 , where r represents the radius. Spheres are significant in various fields, including geometry, physics, and engineering.