Step 1: Use the isotropic elasticity relation between Young’s modulus \(E\), shear modulus \(G\) and Poisson’s ratio \(\nu\):
\[
G=\frac{E}{2(1+\nu)}.
\]
Step 2: Substitute \(E=3.6\ \text{kPa}\) and \(\nu=0.2\):
\[
G=\frac{3.6}{2(1+0.2)}=\frac{3.6}{2.4}=1.5\ \text{kPa}.
\]
Thus, the shear modulus is \(\boxed{1.5\ \text{kPa}}\).