Can you solve 18th q:

18. In Fig. 3.188. ABCDA is a uniform circular wire of  resistance 2$\Omega$. AOC and BOD are two wires along two perpendicular diameters of the circle, each having same resistance 1 $\Omega$. A battery of emf $\xi$ and internal resistance r is connected between point A and D. calculate the equivalent resistance of the network. ]

$\left(Ans. \frac{15}{14}\Omega \right)$