What is the formula used to calculate the surface area of a sphere?

To determine the surface area of a sphere, the correct formula is indeed the one that states Surface Area = 4πr². This formula derives from the geometric properties of a sphere, which is a three-dimensional shape where all points are equidistant from the center.

In this formula, 'r' represents the radius of the sphere. The reasoning behind the factor of 4π comes from the integration involved in calculating the entire surface area as it encompasses the curved surface of the sphere, accounting for its full three-dimensional nature.

In contrast, the other options provided represent formulas pertinent to different shapes or aspects of circles or spheres. For example, a formula like Surface Area = πr² describes the area of a circle, not a sphere. Understanding the unique properties of these geometric figures helps clarify why the formula for a sphere's surface area specifically includes the factor of 4 and is essential for accurate calculations in HVAC applications where spherical components might be present.