1)... [tex]\frac{a}{3}=\frac{b}{4}=\frac{c}{6}=\frac{26}{13}=2,\\
\rightarrow\,\\a=3*2=6cm\,\,,\,b=4*2=8cm\,\,si\,\,c=6*2=12cm.
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2)... daca laturile congruente au 5 cm atunci,
[tex]P_\Delta=5+5+6=16(cm)\,\,\\
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daca laturile congruente sunt de 6 cm atunci,
[tex]P_\Delta=6+6+5=17(cm)[/tex]