13) Lungimile laturilor pot fi:
(18, 18, 9) sau (27, 27, 18) sau (18, 18, 27)
14)
Fie a, b, c lungimile celor trei laturi.
[tex]\it \mathcal{P}=a+b+c=24\ cm\ \ \ \ \ (1)\\ \\ \{a,\ b,\ c\}\ d.\ p.\ \{3,\ 4,\ 5\} \Rightarrow \dfrac{a}{3}=\dfrac{b}{4}=\dfrac{c}{5}=\dfrac{a+b+c}{3+4+5}\ \stackrel{(1)}{=}\ \dfrac{24}{12}=2\ \ \ \ \ (2)\\ \\ \\ (2)\Rightarrow\ \begin{cases}\it \dfrac{a}{3}=2 \Rightarrow a=3\cdot2=6\ cm\\ \\ \it \dfrac{b}{4}=2 \Rightarrow b=4\cdot2=8\ cm\\ \\ \it \dfrac{c}{5}=2 \Rightarrow c=5\cdot2=10\ cm\end{cases}[/tex]
