Here's how to convert -100°C to Kelvin and Fahrenheit:

Celsius to Kelvin

* Formula: K = °C + 273.15

* Calculation: K = -100°C + 273.15 = 173.15 K

Celsius to Fahrenheit

* Formula: °F = (°C × 9/5) + 32

* Calculation: °F = (-100°C × 9/5) + 32 = -148°F

Therefore, a piece of dry ice at -100°C is equivalent to 173.15 Kelvin and -148 degrees Fahrenheit.