Question

What is surface area?

Answer 1

Definition of the surface area:

The area is the amount of space occupied by a two-dimensional flat surface. It is calculated in square units.

The surface area of a three-dimensional object is the sum of the area of all the outer surfaces, it is also measured in square units.

For example: The surface of rectangular cuboid is

$$\begin{gathered} \mathrm{Area}=2(5\times 4+4\times 1.5+1.5+5\times 1.5) \\ =67\mathrm{sq}-\mathrm{unit} \end{gathered}$$

Hence, the surface area of a three-dimensional object is the total area of all its faces.