Final answer:
Surface area is the total area of the object's outer shell, calculated by adding up the areas of all the faces. It is measured in square units.
Step-by-step explanation:
Surface area is the total area of the object's outer shell. It is the sum of the areas of all the faces or surfaces of the object. It is measured in square units.
For example, if we have a cube, its surface area is calculated by adding up the areas of all six faces - the area of one face multiplied by 6.
Keyword 1: Surface area
Keyword 2: Outer shell
Keyword 3: Square units
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