The formula to convert degrees Fahrenheit (°F) to degrees Celsius (°C) is:

°C = (°F - 32) × 5/9

Here's how it works:

1. Subtract 32 from the Fahrenheit temperature: This accounts for the difference in the zero points of the two scales.

2. Multiply the result by 5/9: This adjusts for the different size of the degrees on the Fahrenheit and Celsius scales.

Example:

To convert 77°F to Celsius:

* (°F - 32) = (77 - 32) = 45

* 45 × 5/9 = 25°C

Therefore, 77°F is equal to 25°C.