Find the length of 13.2 kg of copper wire of diameter 4 mm,

Density of copper = Weight/Volume = 8.4 gram/1 cm3 = 8.4 gram/cm3

Volume $=$ Weight $/$ Density $=13.2 \mathrm{~kg} \times 1000 \mathrm{gram} / \mathrm{kg} / 8.4 \mathrm{gram} / \mathrm{cm}^{3}=1571.43 \mathrm{~cm}^{3}$

$\mathrm{L}=\frac{V}{\pi r^{2}}=\frac{1571.43 \mathrm{~cm}^{3}}{\frac{22}{7} \times(0.2 \mathrm{~cm})^{2}}=12500.01 \mathrm{~cm}=125 \mathrm{~m}$

Thus, length of 13.2 kg of copper is 125 m.