From the figure.
        AC₁ = AC₂ = C₁ C₂ = radius
$\therefore$     $\angle {\text{AC}}_1\text{B}=120^0$                                         

In between A and B, 4 resistances are in parallel 

Hence the resistance of four sections are in parallel
Hence equivalent resistance R across AB is
$\frac{1}{\text{R}}=\frac{1}{24}+\frac{1}{12}+\frac{1}{12}+\frac{1}{24}$
or    $\text{R}=4\Omega$
$\therefore$ Power $\frac{{\text{V}}^2}{\text{R}}=\frac{{\left(20\right)}^2}{4}=100\text{ watt}$