The term you are looking for is surface area.
Surface area refers to the total area of the external surfaces of a three-dimensional object. It is a critical concept in geometry as it helps us understand the extent of an object’s outer layer. Measuring surface area is important in various fields, including engineering, architecture, and environmental science, where it can affect heat transfer, chemical reactions, and material use.
For example, the surface area of a cube can be calculated using the formula: Surface Area = 6 × side², where ‘side’ is the length of one edge of the cube. Similarly, for a cylinder, the surface area can be calculated with the formula: Surface Area = 2πr(h + r), where ‘r’ is the radius of the base and ‘h’ is the height. Different shapes will have different formulas, but the underlying principle remains the same: surface area measures the total area of all the surfaces that constitute the object.