Question

Are a parallelogram and a pentagon always sometimes or never similar

Answer 1

Never similar. Because a pentagon does not have a parallel side to it. Hope this helps. 

Answer 2

They are never similar. In order for two shaped to be similar, they must have the same number of sides, and the angles all must be the same. The only difference between two similar shapes is that their side lengths proportionally larger or smaller.

Since a parallelogram has 4 sides, and a pentagon has 5 sides, they can never be similar.