In ABC, the lengths of sides AC and AB are 12 cm and 5 cm, respectively. If the area of Δ A B C is 30 cm^2 and R and r are respectively the radii of…

In $\displaystyle \triangle \mathrm{ABC}$, the lengths of sides AC and AB are $\displaystyle 12$ cm and $\displaystyle 5$ cm , respectively. If the area of $\displaystyle \Delta A B C$ is $\displaystyle 30 \mathrm{~cm}^2$ and R and r are respectively the radii of circumcircle and incircle of $\displaystyle \Delta A B C$, then the value of $\displaystyle 2 \mathrm{R}+\mathrm{r}$ (in cm) is equal to \_\_\_\_.