Hello, Circuit: 1. The problem statement, all variables and given/known data Determine the net resistance between points a and c and a and b. Assume R' ≠ R. 2. Relevant equations ε - IR = 0 V = IR 3. The attempt at a solution http://i.imgur.com/Y2KPI20.jpg I applied an emf between the points a and c, and tried to solve using Kirchhoff's rules. The question suggests me to use symmetry at junctions but I can not see any. Thanks in advance.