Good question, I've never really questioned exchanges, how can you even trust google? I believe there was a price estimator that used on chain data to estimate the price, but I can't find it
Discussion
Again price is a very dynamic discovery type of thing the only way price can be actuated is through the aggregation of the data of buy and sell orders on open markets but there is a way that they have created to try to find out they're quite priced using on chain metrics it is called UTXOracle.py