Correct.

$\displaystyle\frac{{{A}{B}}}{{{D}{E}}}=\frac{{{B}{C}}}{{{E}{F}}}=\frac{{{A}{C}}}{{{D}{F}}}\usepackage{cmbright}\Huge\$

Fill in 3, 4, and 5 for the numerators and substitute the given side length of $\displaystyle\Delta{D}{E}{F}\usepackage{cmbright}\Huge\$ in the denominator to find the other side lengths.