jmc

Let $x$ and $y$ be the width and length of one of the five rectangles, respectively.



Then $3x=2y$ and $5x+4y=176$. Solving for $x$ and $y$, we find $x=16$ and $y=24$. Hence, the perimeter of one of the five congruent rectangles is $2x+2y=\boxed{80}$.