Răspuns: [tex]\bf Aria = \dfrac{9\sqrt{3}}{4}[/tex]
Explicație pas cu pas:
Salutare!
[tex]\boxed{\bf \color{crimson} Perimetru = 3\cdot \ell}[/tex]
[tex]\boxed{\bf \color{crimson} Arie~triunghi~echilateral = \dfrac{\ell^{2}\sqrt{3}}{4}}[/tex]
[tex]\bf 9 = 3\cdot \ell~~\bigg|:3\implies \ell = 3~cm[/tex]
[tex]\bf Aria = \dfrac{3^{2}\sqrt{3}}{4} = \dfrac{9\sqrt{3}}{4}[/tex]
#copaceibrainly
