Fie r₁ ,r₂,r₃ rezistentele pe ramurile a ,b respectiv AC
R_AC=(r₁+r₂)r₃/(r₁+r₂+2r₃)
R_BD=[2r₁r₂+r₃(r₁+r₂)]/(r₁+r₂+2r₃)
R_BD/R_AC=[2r₁r₂+r₃(r₁+r₂)]/(r₁+r₂+2r₃)/(r₁+r₂)r₃/(r₁+r₂+2r₃)=[2r₁r₂+r₃(r₁+r₂)]/(r₁+r₂)r₃
r₁=ρa/S
r₂=ρb/S=4ρa/3S
r₃=ρ√(a²+b²)/S=ρ√(a²+16a²/9)/S=5ρa/3S
R_BD/R_AC=[2r₁r₂+r₃(r₁+r₂)]/(r₁+r₂)r₃=[2ρa*4ρa/3S*S+5ρa/3S(ρa/S+4ρa/3S)]/5ρa/3S(ρa/S+4ρa/3S)=(8ρ²a²/3S²+35ρ²a²/9S²)/35ρ²a²/9S²=59ρ²a²/9S²/35ρ²a²/9S²=59/35=>R_BD/R_AC=59/35
