[tex]\it \mathcal{A} =\ell^2 \Rightarrow \ell^2=\mathcal{A}
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a)\ \ \ell^2= 49 \Rightarrow \ell^2=7^2 \Rightarrow \ell = 7\ cm
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b)\ \ \ell^2= 6,25 \Rightarrow \ell^2=2,5^2 \Rightarrow \ell = 2,5\ cm
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c)\ \ \ell^2= 9,61 \Rightarrow \ell^2=3,1^2 \Rightarrow \ell = 3,1\ cm [/tex]
