# can resistance be found without knowing length? is it possible to find to resistance without knowing the length? i am tryigng to solve a problem that requires me to find the resistance.I cant seem do so without knowing the length of the circuit which is not given.Is there something that shows resistance without knowing the length or am i just looking at problem all wrong?other details include: resistivity of the upper resistance=4ohm metre,resistivity of the lower resistance=2ohm metre,battery emf V=10pi ohm, radius of the circle=1m,angle between A and B is 60.is there a special relation between resistances in parallel?

• If all you know is the resistivity then you need to know the length because resistance = resitivity * length/area. However this is a somewhat special case. If you edit your question to give more details of the problem, and the ways in which you've attempted to solve it, then I'll have a look. – John Rennie Oct 16 '13 at 7:46
• other details include: rho of the upper resistance=4ohm metre,resistivity of the lower resistance=2ohm metre,battery emf V=10ohm, radius of the circle=1m,angle between A and B is 60. – Keith Rebello Oct 16 '13 at 7:55
• Here's a hint: what do you know about the relationship between the radius of a circle and its diameter? – Nathaniel Oct 16 '13 at 8:15
• Using the arc-sector relationship for a circle. – Lugo Oct 16 '13 at 8:40
• – John Rennie Oct 16 '13 at 9:27

Length of the upper half is, $$\pi /3*r$$
And the length of the lower half is $$2\pi/3*r$$ $R_1$ and $R_2$ are in parallel.