Three 2 ohm resistors are connected to form a triangle. The resistance between any two corner is

The triangular arrangement is equivalent to a parallel combination of two ohm resistance and 4 ohm resistance (two resistances are in series). Therefore
$\begin{array}{l}\frac{1}{\mathrm{R}}=\frac{1}{2}+\frac{1}{4}=\frac{2+1}{4}=\frac{3}{4}\\ \mathrm{R}=\frac{4}{3}\mathrm{ohm}\end{array}$
Hence the resistance between any two corner is 4/3 ohm.