Relative poverty is not having enough money to maintain the standard of living that is customary in that society.

The absolute poverty line is found by finding the total cost of all the essential resources that an average human adult consumes in one year. Determined by the world bank. This is adjusted for purchasing power parity. In other words, it applies internationally. The absolute american poverty line is just the international absolute poverty. And there's no need for a relative poverty line, it's rather a nonsense concept.