[tex] P_{patrat} = P_{dreptunghi} [/tex]
4*[tex] 4l_{patrat} =2(L+9)[/tex]
4*12=2L+18
48=2l+18
2L=48-18
2L=30
L=15 ( lungimea dreptunghiului)
[tex] A_{dreptunghi}=L*l=15*9=135 m^{2} [/tex]
[tex] A_{patrat} = l^{2} =12*12=144 m^{2} [/tex]
g= grau
p=porumb
g+p=135 m²
[tex] \frac{g}{4} = \frac{p}{5} =k[/tex]
g=4k
p=5k
4k+5k=135 m²
9k=135 m²
k=15
g=4*15=60 m²
p=5*15=75 m²
