Please help me im very depressed and im struggling a lot on my math and i really need some answers Which number sentence is true?

What is the length of bc ? enter your answer in the box.bc =

In the field of thermodynamics, rankine is the unit used to measure temperature. one can convert temperature from celsius into rankine using the formula c= r/1.8 - 273, what is the temperature in celcius corresponding to r degrees rankine.

How can you tell when x and y are not directly proportional?