Density = mass/volume
Volume = 0.3 x 2.1 x 0.1 = 0.063 mi³
Density = 0.07 ÷ 0.063 = 1.1 kg /mi³
Answer: 1.1 kg /mi³
Volume = 7 x 4 x 10 = 280 dm³
Density = 10690.4 ÷ 280 = 38.16L / dm³
Answer: 38.16L / dm³
Density = 8550405 ÷ 1213.4 = 7047 people / km²
Answer: 7047 people / km²