Areas of Parallelograms, Triangles, and Trapezoids
Concept

Parallelogram

A parallelogram is a quadrilateral with two pairs of parallel sides. Parallelograms can be divided into three main types: rectangles, rhombuses, and squares.
Parallelogram
The following properties are true for all parallelograms.
Property Justification
The opposite sides are congruent Parallelogram Opposite Sides Theorem
The opposite angles are congruent Parallelogram Opposite Angles Theorem
The diagonals bisect each other Parallelogram Diagonals Theorem
These properties are illustrated graphically in the next diagram.
Parallelogram