The formula for converting between temperature scales is often one of the formulas printed on the inside of one of the covers of your Physics text book. (Why do I get the creepy feeling that I need to explain what a 'book' is now ?)
Anyway, be that as it may, and it probably is, the formula to take a Fahrenheit temperature and convert it to a Celsius one is
°C = (5/9) x (°F - 32°)
°C = (5/9) x (125° - 32°)
°C = (5/9) x (93°)
°C = (51 and 2/3)°
