Properties of Quads - Rhombus is a parallelogram
Rhombus – a quadrilateral with four congruent sides
Observation 1: Rhombus is a parallelogram.
Proof follows from the congruence of the triangles ABD and CDB.
This congruence help us reveal the relationships between some of the angles
and that in turn helps us explain why opposite sides must be parallel.
Observation 2: Opposite angles in a rhombus are congruent.
The same triangle congruence can be used to explain it. Can you see
how it shows that angles at the vertices C and A are congruent?
What would you do to show that angles at the vertices D and B are also
congruent?