Răspuns :
Răspuns:
P=2(L+l)
L=4/13 din P=>L=4/13·2(L+l)
L=l+6
6+l=4/13·2(6+l+l)
6+l=8/13·(6+2l)
78+13l=8·(6+2l)
78+13l=48+16l
16l-13l=78-48
3l=30=>l=30:3=>l=10 cm
L=6+l=6+10=>L=16 cm
Raspuns:
16 cm - lungimea dreptunghiului
10 cm - latimea dreptunghiului
Explicație pas cu pas:
Salutare!
[tex]\bf L= \dfrac{4}{13} \cdot P[/tex]
[tex] \bf L = 6 + l[/tex]
Perimetrul = 2•(L+l)
L = lungimea
l - latimea
[tex]\bf L= \dfrac{4}{13} \cdot 2\cdot(L+l)[/tex]
[tex]\bf L= \dfrac{8}{13}\cdot(L+l)[/tex]
Egalam cele doua relatii:
[tex]\bf 6+l = \dfrac{8}{13} \cdot (L+l)\:\: \Big|\cdot 13[/tex]
[tex]\bf 78 +13l = 8(L+l)[/tex]
[tex]\bf 78+13l = 8(6+l+l)[/tex]
[tex]\bf 78 +13l = 48+16l[/tex]
[tex]\bf 78 = 48+16l-13l[/tex]
[tex]\bf 78 = 48+3l[/tex]
[tex]\bf 78 -48 = 3l[/tex]
[tex]\bf 30 = 3l\:\:\Big|:3[/tex]
[tex]\boxed{\bf l = 10\: cm}[/tex]
[tex]\bf L = 6+10\implies \boxed{\bf L =16\:cm}[/tex]
==pav38==