ra, re, ri, ka, ke, ki are possessives, which one to use depends on gender of subject only
ex
naam is masculine so u will always say
meRA naam(my name)(doesnt matter if u r a girl or boy)
usKA naam(his/her name)
kiska naam??(whos name)
ex.2
kitaab(book) is femenine so u will always use ri or ki to show possession
ex. meri kitaab(my book )
uski kitaab(his/ her book)
humaari kitab(our book)
ghar(home) masculine
mera ghar
uska ghar
humara ghar
so repeating again, with "naam" always mera (or mere) is used and "meri" is never used.