Răspuns:
Latimea =x ; L =5X ; X+X+5X+5X=PERIMETRU=144
Explicație pas cu pas:
12X=144 ; X=144:12=12; l=12 ; L=5 ×12=60
[tex]\it \mathcal{P}=144 \Rightarrow p=\dfrac{\mathcal{P}}{2}=\dfrac{144}{2}=72\ cm\\ \\ \\ \\p=L+\ell=72\ \ \ \ \ \ (1)\\ \\ \\ L>\ell\ de\ 5\ ori \Rightarrow L=5\ell\ \ \ \ \ (2)\\ \\ \\ (1),\ (2) \Rightarrow 5\ell+\ell=72 \Rightarrow 6\ell = 72|_{:6} \Rightarrow \ell=12\ cm\ \ \ \ \ (3)\\ \\ \\ (2),\ (3) \Rightarrow L = 5\cdot12 \Rightarrow L=60\ cm.[/tex]
