A parallelogram is a four-sided shape, known as a quadrilateral, where opposite sides are both equal in length and parallel. This means that the two pairs of opposite sides never meet, no matter how far they are extended. Common examples of parallelograms include rectangles, rhombuses, and squares, which all have unique properties but share the basic characteristics of a parallelogram. In a parallelogram, the opposite angles are also equal, and the adjacent angles are supplementary, meaning they add up to 180 degrees. The area of a parallelogram can be calculated by multiplying the base length by the height. This geometric shape is often studied in mathematics and is important in various fields, including architecture and engineering.