1 lb ≈ 0.454 kg
1 in ≈ 2.54 cm
I'm not sure I understand the "do not" part of this question. What does it mean to convert from cubic inches (volume) to inches (length), and from centimeter to cubic centimeters?
In any case, you have
(1 lb)/(32.375 in³) ≈ (1 lb)/(3.19 in)³
… ≈ (1 lb)/(3.19 in)³ × (0.454 kg)/(1 lb) × ((1 in)/(2.54 cm))³
… ≈ (0.454 kg)/(3.19 in)³ × ((1 in)/(2.54 cm))³
… ≈ (0.454 kg) × ((1 in)/((3.19 in) × (2.54 cm))³
… ≈ (0.454 kg) × (1/(8.10 cm))³
… ≈ (0.454 kg) × 1/(530.531 cm³)
… ≈ (0.454 kg)/(530.531 cm³)
… ≈ 0.000856 kg/cm³