[tex]ro = \frac{2.7g}{ {cm}^{3} } = \frac{2.7 \times {10}^{ - 3} kg}{ {10}^{ - 6} {m}^{3} } [/tex]
[tex] ro = \frac{m}{v} = > m = ro \times v = \frac{2.7 \times {10}^{ - 3} kg}{ {10}^{ - 6} {m}^{3} } \times 4 \times{10}^{ - 2} = \frac{2.7 \times {10}^{ - 3} kg}{ {10}^{ 3} {m}^{3} } \times 4 = 2.7 \times 4 × 10^{-1} = 1,08kg[/tex]
