Let A be the set of all triangles in a plane. Let R be the relation in A defined as R = { ( x , y ) : x is congruent to y }. then R is

Not a transitive relation Reflexive , symmetric but not transitive An equivalence relation Not a symmetric relation

An equivalence relation

For every x ∈ set of triangles x is congruent to itself ⇒ reflexive $x≅y⇒y≅x$   (reflexive) $x≅y,y≅z,x≅z$ (transitive) ⇒ relation is equivalence