a) Never
{All angles of a rectangle are right}
b) Always
{all sides of a rhombus are the same, 4×13=52}
c) Always
{oposite angles of a paralleogram are congruent}
d) Never
{parallel sides has the same slope}
e) Always
{square has all sides of the same length, so it is rhombus}
f) Sometimes
{Only if it has angles of 90°}
