Think of two perfect squares that surround 29. The number 29 is between the perfect squares 25 and 36. So $\displaystyle\sqrt{{{29}}}\usepackage{cmbright}\Huge\$ must be between $\displaystyle\sqrt{{{25}}}\usepackage{cmbright}\Huge\$ and $\displaystyle\sqrt{{{36}}}\usepackage{cmbright}\Huge\$ .

$\displaystyle\sqrt{{{25}}}={5}\usepackage{cmbright}\Huge\$ and $\displaystyle\sqrt{{{36}}}={6}\usepackage{cmbright}\Huge\$ , so $\displaystyle\sqrt{{{29}}}\usepackage{cmbright}\Huge\$ falls between 5 and 6.