Cześć!
Zadanie 1
[tex]\text{P}=a\cdot b\\\\a=8 \ cm, \ b= \ ?, \ \text{P}=168 \ cm^2\\\\8 \ cm\cdot b=168 \ cm^2\\\\b=168 \ cm^2:8 \ cm\\\\b=21 \ cm\\\\\text{Ob}=2\cdot(a+b)=2\cdot(8 \ cm+21 \ cm)=2\cdot29 \ cm\\\\\boxed{\text{Ob}=58 \ cm}[/tex]
Odp. Obwód tego prostokąta wynosi 58 cm.
Zadanie 2
[tex]1 \ m^2=(100 \ cm)^2=\boxed{10 \ 000 \ cm^2}\\\\2 \ cm^2=2\cdot(0,01 \ m)^2=2\cdot0,0001 \ m^2=\boxed{0,0002 \ m^2}\\\\1 \ a=100 \ m^2\\\\1 \ m^2=(0,001 \ km)^2=\boxed{0,000001 \ km^2}[/tex]
