There are two pints every quarter.
So let's convert pints to quarter
[tex]\frac{4\frac{1}{2} }{2} =\frac{\frac{9}{2} }{2} = \frac{9}{4}[/tex]
There 4 1/2 pint is to 9/4 quarter.
Hope that helps!
p.s. look at my diagram to help you remember