Cześć!
1)
[tex]1 \ m=100 \ cm, \ dlatego \ 1 \ m^3=(100 \ cm)^3=1 \ 000 \ 000 \ cm^3\\\\1 \ cm^3=0,000001 \ m^3\\\\721 \ cm^3=721\cdot0,000001 \ m^3=\boxed{0,000721 \ m^3}[/tex]
2)
[tex]25 \ \dfrac{kg}{m^3}=25\cdot\dfrac{1000 \ g}{1000000 \ cm^3}=(25\cdot0,001) \ \dfrac{g}{cm^3}=\boxed{0,025 \ \frac{g}{cm^3}}\\[/tex]
