Question

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Answer 1

$\bf 5.\ \ \it \mathcal{A}=\ell^2=81=9^2 \Rightarrow \ell = 9\ cm\\ \\ \mathcal{P}=4\cdot\ell=4\cdot9=36\ cm\\ \\ \\ \bf6.\ \ \it \mathcal{P}=2(L+\ell)=40|_{:2} \Rightarrow L+\ell=20 \Rightarrow L=20-\ell\ \ \ \ (1)\\ \\ L>\ell\ cu\ 2 \Rightarrow L=\ell+2\ \ \ \ \ (2)\\ \\ (1),\ (2) \Rightarrow \ell+2=20-\ell \Rightarrow \ell+\ell=20-2 \Rightarrow 2\ell=18|_{:2} \Rightarrow \ell=9cm\ \ \ \ \ (3)\\ \\ (2),\ (3) \Rightarrow L=9+2 \Rightarrow L=11cm$

$\it \mathcal{A}=L\cdot\ell=11\cdot9=99\ cm^2$

Answer 2

Răspuns:

SALUT

Problema 5:>>>

A pătrat = 81 cm^2 =>V81 = 9 (cm).

P pătrat = l*4 = 9*4 = 36 (cm).

Problema 6:>>>

P ABCD => 40 cm.

P = 2L+2l

40 = 2(l+2)+2l

40 = 2l+4+2l

4l = 40-4 => 36

l = 36:4 => 9 (cm)

L = 9+2 => 11(cm)

A abcd = L*l = 11 * 9 = 99 cm^2.