How can this relation be anti-symmetric and symmetric at the same time?

Question

Why is this anti-symmetrical and symmetrical at the same time? I get how it is anti-symmetric because There is no pair such as (1,2) & (2,1) but how did it become symmetrical?

R is a relation on the set of integers
R = {(a,b) | a = b}

Answer 1

If $(a,b)$ is in $R$ then $a=b$ [by the definition given for $R$] so $(b,a)=(a,b)$ so $(b,a)$ is in $R$.