l=R=6 cm
a)
[tex]A_{ABCO}=A_{hex}:3\\\\A_{hex}=\frac{6l^2\sqrt{3} }{4} =54\sqrt{3} \ cm^2\\\\A_{ABCO}=18\sqrt{3} \ cm^2[/tex]
b)
[tex]A_{OED}=A_{hex}:6=9\sqrt{3} \ cm^2[/tex]
[tex]A_{AOEF}=2\cdot A_{OED}=18\sqrt{3}\ cm^2\\\\ A_{AED}=A_{OED}+\frac{A+{AOEF}}{2} =18\sqrt{3} \ cm^2[/tex]
Un alt exercitiu gasesti aici: https://brainly.ro/tema/972729
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