The strain of a material is given by:
[tex]\epsilon=\frac{\Delta L}{L_0}[/tex]where L0 is the original length. Plugging the values given and solving for the change in length we have:
[tex]\begin{gathered} 0.82=\frac{\Delta L}{100} \\ \Delta L=(0.82)(100) \\ \Delta L=82 \end{gathered}[/tex]This means that the lenght of the rod change in 82 cm, therefore the new length is 182 cm.