Question

un dreptunghi are lungimea de 3 ori mai mare decat latimea.Afla perimetrul dreptunghiului, stiind ca aria acestuia este 675 cm2​

Answer 1

L= 3l

Aria= L*l  

675 = 3l*l

3l^2  = 675

3l = V675

3l = 15V3

l = 15V3/3

l = 5V3 cm

L = 5V3*3 = 15V3 cm

Perimetrul = 2(L+l)  = 2*(15V3+5V3) = 2*20V3 = 40V3 cm

Answer 2

$\it L= 3\ell\\ \\ \mathcal{A}=675\Rightarrow L\cdot\ell=675\Rightarrow 3\ell\cdot\ell= 675|_{:3} \Rightarrow \ell\cdot\ell=225 \Rightarrow \ell\cdot\ell=15\cdot 15 \Rightarrow\\ \\ \ell=15\ cm \\ \\ L=3\cdot15=45\ cm\\ \\ \mathcal{P}=2(L+\ell)=2(45+15)=2\cdot60=120\ cm$