Calculating depreciation when tax assessment is less than purchase price???

[Matthew Allison]

Hi everyone, thanks for the help in advance! I am having trouble identifying what my cost basis is for my rental property. My 2021 real estate assessment came out at $185,000, of which $50,000 was land and $135,000 was the building and my purchase price was $238,000. Of what I have read, most places say my cost basis is $238,000(PP) - $50,000(land) =$188,000. Yet I have seen other articles saying that it should be the ratio of building/total ($135,000/$185,000) which is 73% to the purchase price. Landing it at $173,675. Does anyone know the proper way?

Additionally, do I have to use the year of purchase assessed values (2021) or since I lived in my home for a year and then rented it out in 2022, can I use the 2022 real estate assessment?