If it is your surface then whatever you like. And if it is not yours, then nothing - without the owner's permission.
A flat surface is no more that a plain horizontal surface with no depth. For example the surface of a table top is a flat surface, that is the surface only, not the depth of the top or the rest of the table
Plate Tectonics, to put it simply.
It does not have a flat surface.
You place your bottom on a flat, level surface; and put your weight on it. It's that simple.
A flat, level surface is a plane.
A plane is a flat surface with no thickness
The flat surface that goes on and on in all directions has no boundaries. This flat surface is called infinite surface. Accordingly, the answer is that the flat surface that goes on and on in all directions is called an infinite surface.
The surface area of a cone is: Curved Surface: pi X the radius X L (L is the slant of the cone pointing to the tip. \ ) Flat Area/Base: pi X the radius *squared* easy.
Its base is a flat surface
It is a drawing of the earth on a flat surface
A mirror with a flat surface - planar
A flat surface generally refers to a horizontal surface and is referred to as the plane.