Math Class 11 Chapter 1 - Number System

If a belongs to R, a = a; represents? If a, b belongs to R, a = b =# b = a represents? If a, b, c belongs to R, a = b /\ b = e =# a =c represents? If a, b, c belongs to R, a = b =#a+e = b+e? If a, b, f, belongs to, a+c = b+c =# a = b represents? If a, b Belongs to R, either a = b or a # b or a @ b represents? In circle is the circle which touches one side of triangle externally and two sides internally when produced? In order to bear the burden of bridges, arches below the bridges are constructed in the form of triangles?