7) 15.5kg..............55.18 lei
2.3kg....................x x=(55.18*2.3)/15.5=8.18 lei
8) ABCD-dreptunghi.
L=3l
P=105.2 cm
P=2L+2l
105.2=(2*3l)+2l
105.2=6l+2l
105.2=8l⇒l=13.5 cm
L=3*13.5=39.45 cm
9) a+b=32.45
c+d=403.009
M=?
M=(a+b+c+d)/4
M=(32.45+403.009)/4
M=108.86
10) S=1003.9
D=?
S-D=432.5+0.004
S-D=432.504
1003.9-D=432.504
D=1003.9-432.504
D=571.396
