線路電壓降與線路電阻成正比
3%:X = ρ 𝓁1.62 : ρ 𝓁22
3%:X = 11.6 × 1.6 : 14 (交叉相乘)
3%:X = 4 : 1.6 × 1.6
3%:X = 1 : 0.4 × 1.6
X = 3% × 0.4 × 1.6 = 1.92%