Is 27/51 equal to 18/34

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.

Extra points! find the missing dimension! need asap

Can someone me with this graph problem by the way i need to know the answers by today since this assignment is due ! !