If a conductor of length l and cross-sectional area A has resistivity ρ, halving the length AND halving the area gives new resistance

1. Original resistance R = ρ l / A. 2. Half length: l → l/2. Half area: A → A/2. 3. New R' = ρ (l/2) / (A/2) = ρ l / A = R. 4. So halving both length and area leaves the resistance unchanged. _Source: syllabus Physics, Ch 3 "Current Electricity", §3.4_