Answer
$(a) \space 0.0345 \space g/cm^3$
Work Step by Step
edge length = $0.750 \space m \times \frac{100 \space cm}{1 \space m} = 75.0 \space cm$
$$V = (75.0 \space cm)^3 = 4.22 \times 10^5 \space cm^3$$
$m = 14.56 \space kg \times \frac{1000 \space g}{1 \space kg} = 1.456 \times 10^4 \space g$
$$d = \frac{m}{V} = \frac{1.456 \times 10^4 \space g}{4.22 \times 10^5 \space cm^3} = 0.0345 \space g/cm^3$$
