[tex]30min=0.5h\\\\\frac{1}{4}inch=0.25inch\\\\4\frac{1}{2}h=4.5h[/tex]
[tex]0.25inch\ -\ 0.5h\\\\2\cdot0.25inch\ -\ 2\cdot0.5h\to0.5inch\ -\ 1h\\\\\\0.5inch\ -\ 1h\\0.5inch\ -\ 1h\\0.5inch\ -\ 1h\\0.5inch\ -\ 1h\\0.25inch\ -0.5h\\------------+\\2.25inch\ -\ 4.5h[/tex]
