rational vs. irrational numbers
I am reading a text book and it says that in the equations to change degrees Fahrenheit to degrees Celsius and in the opposite equation:
F = (9/5)(C)+32
C = (5/9)(F-32)
that 9/5 is a rational number and 5/9 is an irrational number.
I don't understand because the definition of rational numbers is numbers that have the form a/b.