* Opposite sides are parallel. This means that the lines extending the sides would never intersect.
* Opposite sides are congruent. This means that the opposite sides have the same length.
* Opposite angles are congruent. This means that the opposite angles have the same measure.
* Consecutive angles are supplementary. This means that the angles next to each other add up to 180 degrees.
Here's a visual representation:
[Image of a parallelogram with labels for sides and angles, highlighting parallel sides and congruent angles]
Note: While all parallelograms share these properties, they can also have additional specific properties depending on the shape. For example, a rectangle is a type of parallelogram with four right angles, and a rhombus is a type of parallelogram with four congruent sides.