In 1954, the tenth general conference on weights and measures adopted the Kelvin K as the basic unit for measuring all international weights and measures. While the kelvin is the standard unit, degrees Farenheit and degrees Celsius are still in common use in the United States.
The function C(F)=5/9(F-32) relates Celsius temperatures and Farenheit Temperatures. The function K(C)= C + 273.15 relates celsius temperatures and kelvin temperatures.
Let’s convert Fahrenheit to Kelvin. The composition of the function K with the function C is
K(C(F)) = C(F) + 273 = (5/9)(F-32) + 273
Since C converts Fahrenheit to Celsius and K converts Celsius to Kelvin, the composition will convert Fahrenheit to Kelvin.