1)
Stiind urmatoarele formule P=2x(L+l) si respectiv A=Lxl ->
deci L=2l
inlocuind in formula perimetrului: 2x(2l+l)=72, 3l=36, l=12
de aici rezulta ca L=2x12=24
inlocuind in formula ariei : A=Lxl=24x12= 288
solutia A=288
2) a)Rezolvare:
L=2,2 }
l=1,3 } V=Lxlxh V=2,2x1,3x0,9=2,574 dm³
h=0,9 } Af= 2(Lxl +Lxh+lxh)
Af=(2,2x1,3+2,2x0,9+0,9x1,3)
Af=2(2,86+1,98+1,17)=2x6,01=12,02 dm²
V=2,574dm³
Af=12,02 dm²
b)
daca pt 1 dm².........15kg vopsea
12,02dm²..........x g?
Xx12,02 x15g=180,3gr
180,3gr=0,1803 l
