Your great grandfather's nephew was your grandfather's first cousin. You are two generations removed from your grandfather and his cousin. Therefore you and your great grandfather's nephew are first cousins, twice removed.
cousin
3rd cousin
Your great great grandfather.
Most likely they would not be related to you
Friedrich Ludwig Jahn
Your grandfather's niece is a first cousin of one of your parents. Her son is your second cousin.
The possessive form of the plural noun grandfathers is grandfathers'.example: Both of my grandfathers' names are George.
my 6th greatgrandfather was a mulatto, I'm a female, what pecentage am I?
No, Greatgrandfather Tommy didn't use ochre
Your grandmother is first cousins with cousin. Your parent would be the second cousin of the cousin's son. That would make you second cousins once removed.
No he is a 105 year old man who is my greatgrandfather he is a total mad person
Your grandfathers' sisters' grandchildren are your second cousins.