How’d they figure that?
In reality, i think someone was looking at the stereotypes of Jesus, tall, long golden hair, etc, and they figured, based on averages, if he was living in that place in time he was probably around that tall, and that someone would have mentioned what a gigantic freak he was if he had been up around 190. He was probably also dark enough that he could have been considered....... black. Of course the Vatican weren't buying any of it.