13. 5 identical rectangles are placed inside a square, with all the sides of the rectangles parallel to the corresponding sides of the square, and the side length of the square is 24 cm. Find: the area of a single rectangle.
【Answer】 32
【Solution】Assume the length of the rectangle is $x$ and the width is $y$, then $\left\{\begin{array}{l}3 x=24 \\ 2 x+2 y=24\end{array} \Rightarrow\left\{\begin{array}{l}x=8 \\ y=4\end{array}\right.\right.$, so the area of the rectangle is $32 \mathrm{~cm}^{2}$