Recovery after losing wallet.dat and formatting hard disk

[Bitcoin]

Recovery after losing wallet.dat and formatting hard disk

I have received the bitcoin way back in 2013 in Bitcoin Core. At that time I don't know about the importance of wallet.dat - I have formatted my hard disk and install Bitcoin Core again in 2017 but there it didn't show my Bitcoin in my balance. I have my Bitcoin Key.

I meant "Bitcoin Key" is my Public Key on which I got my bitcoin. Is there any other way to get my Bitcoin back if I didn't get my original wallet.dat of Bitcoin Core?

How can I get my bitcoin back?

How can I get to know my Private Key?

Source: Recovery after losing wallet.dat and formatting hard disk