A combined trapezoidal footing of length $L$ supports two identical square columns  $(P_1$ and $P_{2})$ of size $0.5 \text{ m} \times 0.5\text{ m}$, as shown in the figure. The columns $P_{1}$ and $P_{2}$ carry loads of $2000\text{ kN}$ and $1500\text{ kN}$, respectively.

If the stress beneath the footing is uniform, the length of the combined footing $L$ (in $\text{m}, \textit{round off to two decimal places}$) is ____________________