13. The living room of Filippo's house has a rectangular floor plan. Filippo noticed that if he plugs the vacuum cleaner into the outlet near the entrance door, he can clean the entire floor: this means that all points on the floor are less than $5 \mathrm{~m}$ away from the point on the wall where the outlet is located. What is the maximum area of the living room (in $\mathrm{m}^{2}$)?