Why does the position vector of the surface area of a material act normally(perpendicular)to it??.?

Question

also is 1/log a equal to exponential(a)

Answer 1

A surface area is a plane and a plane can be totally defined by three points.  Define two vectors, one drawn from point A to point B and the second from point A to point C.  The cross product of these two vectors defines the normal to the two vectors and thus to the plane.