Răspuns :
[tex]\it \mathcal{A}_{disc}=\pi R^2=2,56\pi|_{:\pi} \Rightarrow R^2=2,56=1,6^2 \Rightarrow R=1,6\ cm\\ \\ L_{cerc}=2\pi R=2\cdot\pi\cdot1,6=3,2\pi\ cm[/tex]
[tex]\it \mathcal{A}_{disc}=\pi R^2=2,56\pi|_{:\pi} \Rightarrow R^2=2,56=1,6^2 \Rightarrow R=1,6\ cm\\ \\ L_{cerc}=2\pi R=2\cdot\pi\cdot1,6=3,2\pi\ cm[/tex]