## 3. Rectangles

A rectangle is divided by lines parallel to its sides into four smaller rectangles. The areas of three of these four smaller rectangles are $240 \mathrm{~cm}^{2}, 320 \mathrm{~cm}^{2}$, and $480 \mathrm{~cm}^{2}$. What is the area (in $\mathrm{cm}^{2}$) of the largest of the four resulting rectangles?

Result: $\quad 640$