[tex]Dane:\\r = 10 \ mm = 1 \ cm\\m = 15 \ g\\Szukane:\\d = ?\\\\d = \frac{m}{V}\\\\ale:\\\\V = \frac{4}{3}\pi r^{3} = \frac{4}{3}\cdot3,14\cdot(1 \ cm)^{3} = 4,18(6) \ cm^{3}= 4,187 \ cm^{3}\\\\\\d = \frac{15 \ g}{4,187 \ cm^{3}}\\\\d = 3,58\frac{g}{cm^{3}} = 3 \ 580\frac{kg}{m^{3}} = \boxed{3,58\cdot10^{3} \ \frac{kg}{m^{3}}}[/tex]
