[tex]\bold{1.} \\ a=5,5 \ cm\\ m=1 \ 363 \ g \\ \rho = \frac{m}{V} \\ V=a^3= (5,5 \ cm)^3 =166, 375\ cm^3 \\ \rho=\frac{1 \ 363 \ g}{166, 375\ cm^3} \\ \Rightarrow \boxed{\rho=8,2 \ g/cm^3} \\ \bold{2.} \\ V_1=1 \ l=0,001 \ m^3 \\ V_2=2 \ l=0,002 \ m^3 \\ m_1=1 \ 158 \ g=1,158 \ kg \\ m_2=3,6 \ kg \\ \rho=\frac{m}{V}=\frac{m_1+m_2}{V_1+V_2}=\frac{1,158 \ kg+3,6 \ kg}{0,001 \ m^3+0,002 \ m^3}=\frac{4,758 \ kg}{0,003 \ m^3} \\ \Rightarrow \boxed{\rho=1 \ 586 \ kg/m^3}[/tex]
