$\displaystyle{1.57}={2}{\left({3.14}\right)}\sqrt{{\frac{{L}}{{32}}}}\usepackage{cmbright}\Huge\$

$\displaystyle{0.25}=\sqrt{{\frac{{L}}{{32}}}}\usepackage{cmbright}\Huge\$ , so $\displaystyle{{\left({0.25}\right)}}^{{2}}={{\left(\sqrt{{\frac{{L}}{{32}}}}\right)}}^{{2}}\usepackage{cmbright}\Huge\$

$\displaystyle{0.0625}=\frac{{L}}{{32}}\usepackage{cmbright}\Huge\$ , so $\displaystyle{L}={2}\usepackage{cmbright}\Huge\$