Answer
$$m = 10.5 \space kg$$
Work Step by Step
$$V = 52.8 \space cm \times 6.74 \space cm \times 3.73 \space cm = 1330 \space cm^3$$ $$d = \frac{m}{V} \longrightarrow m = V \times d$$ $$m = (1330 \space cm^3) \times (7.86 \space g/cm^3) = 10500 \space g$$ $$m = 10500 \space g \times \frac{1 \space kg}{1000 \space g} = 10.5 \space kg$$
