These statements are true:

This is
true because of the definition of a rhombus which states that opposite sides are parallel.


This is
true because the diagonals of a rhombus bisect each other at right angles.

This is
true because the four sides of a rhombus are all equals.

This is also
true. Two angles are
supplementary when they add up to 180 degrees. Angles in rhombus are equal two to two. Let's name:
Then it is true that:

Besides, a rhombus is a quadrilateral and it is true that the interior angles of a quadrilateral add up to 360 degrees, thus:
