Here's how to convert Fahrenheit to Celsius:

Formula:

Celsius = (Fahrenheit - 32) * 5/9

Calculation:

1. Subtract 32 from the Fahrenheit temperature: 97.8 - 32 = 65.8

2. Multiply the result by 5/9: 65.8 * (5/9) = 36.56

Therefore, 97.8°F is approximately equal to 36.56°C.