You have chosen the two whole numbers between which $\displaystyle\frac{{45}}{{2}}\usepackage{cmbright}\Huge\$ falls, instead of the two whole numbers between which $\displaystyle\sqrt{{{45}}}\usepackage{cmbright}\Huge\$ falls. First find the two perfect squares that surround 45. Take the square roots of those perfect squares to find the two whole numbers.