Răspuns:
Triunghi echilateral, cu R = 8 cm
[tex]\ell = R \sqrt{3} = 8 \sqrt{3} \ cm[/tex]
[tex]r = a = \dfrac{R}{2} = \dfrac{8}{2} = 4 \ cm[/tex]
[tex]\mathcal {A}_{\Delta} = \dfrac{\ell^2 \sqrt{3} }{4} = \dfrac{(8 \sqrt{3})^2 \sqrt{3} }{4} = 48 \ {cm}^{2} \\ [/tex]
[tex]\mathcal {P}_{\Delta} = 3\ell = 3 \cdot 8 \sqrt{3} = 24 \sqrt{3} \ cm[/tex]
[tex]h = \dfrac{\ell \sqrt{3} }{2} = \dfrac{8 \sqrt{3} \cdot \sqrt{3} }{2} = 12 \ {cm}[/tex]
