Hi Mustafa,

I am not sure that I am interpreting your problem but I think you are asking about the surface of a three dimensional object. If that is correct then I have a few suggestions.

First of all if you want to paint the exterior of a house then you need to calculate the surface area in able to decide how much paint you need.

Another example is human lungs.

A third example might be your small intestines. The surface area is approximately the same as the surface area of a tennis court.

You might also consider the total surface area of all the leaves on a tree.

Finally do a web search for the term heat sink. This is a passive device that is used to dissipate the heat, for example in your computer. It works by increasing the surface area in contact with the cooling medium such as air or water.

I hope this helps,
Penny