Sides BC and EF are each 2 units.  Sides AB, CD, DE, and FA are each . 

If point H is (3,7) then AF is the hypotenuse of triangle AHF and it equals  .

Hexagon A is not similar to Hexagon B because the corresponding sides are not in the same ratio.  Hexagon B is a regular hexagon.  Hexagon A is not, therefore, they cannot be similar.