What is 100 K in Celsius?

Hint: The increase and decrease in temperature is measured by the scale called Kelvin, Fahrenheit and Celsius. Hence we can say that Kelvin, Fahrenheit and Celsius are temperature scales. Kelvin is represented by the symbol K, Fahrenheit is represented by the symbol ${}^\circ F$ whereas Celsius is represented by the symbol${}^\circ C$.

Complete step by step answer: Celsius is a temperature scale that can also be known by the name centigrade scale. The degree Celsius ${}^\circ C$can refer to a specific temperature on the Celsius scale or a unit which indicates difference between two temperatures or any uncertainty between them.
Kelvin is said to be the best unit of temperature in SI units where SI stands for International System of Units and having the unit symbol K. Like the degree Fahrenheit and degree Celsius kelvin is not referred to as a degree it is the primary unit of temperature measurement.
Kelvin into Celsius: To convert the temperature unit kelvin to degree Celsius is very easy; it can be done by 273.15 from the Kelvin temperature in order to obtain the required Celsius temperature. The Kelvin scale and the celsius scale are two different temperature scales which are related by the following formula:
$K=C+273.15$ or $C=K-273.15$
C denotes the magnitude of the temperature in degrees celsius and K denotes the magnitude of the temperature in Kelvin
Now 100 K in Celsius can be calculated as:
$C=100-273.15=-173.15$
Hence we can say that -173.15 Celsius are there in 100 K .

Note: Celsius is named after the discoverer name Anders Celsius. The unit of Celsius was called by centigrade which was taken from Latin word centum which has the meaning 100 and gradus which represents steps.