Răspuns :
[tex]\it a)\ \ell = 3\dfrac{2}{11}=\dfrac{35}{11}\\ \\ \\ \mathcal{P}_{\Box}=4\cdot\ \ell=4\cdot\dfrac{35}{11}=\dfrac{140}{11}\ \approx\ 12,7\ cm\\ \\ \\ \mathcal{A}_{\Box}=\ell^2=\Big(\dfrac{35}{11}\Big)^2=\dfrac{1225}{121}\ \approx\ 10,12\ cm^2[/tex]
b) "romb cu latura de 7,5 cm si diagonalele de 4,2cm si 2,6 cm" ... ?!
Un asemenea romb nu există (!)