What is "in parallelogram abcd?

A parallelogram is a quadrilateral with opposite sides that are parallel and equal in length. The opposite angles are also equal in measure.

In parallelogram ABCD:

• AB is parallel to CD
• AD is parallel to BC
• Angle A is equal to angle C
• Angle B is equal to angle D
• The diagonals AC and BD bisect each other
• The sum of the interior angles of a parallelogram is always equal to 360 degrees

Overall, a parallelogram is a special type of quadrilateral that has several unique properties and relationships among its sides and angles.