quad (quadrangle)

A quadrilateral, also called a quad or quadrangle, is a four-sided polygon. It has four straight sides and four angles where the sides meet. The sides can be different in length, and the angles can vary, allowing for many shapes like squares, rectangles, trapezoids, and rhombuses. The total of all interior angles always adds up to 360 degrees. Quadrilaterals are common in everyday structures, such as windows, tiles, and frames, and are fundamental in geometry for understanding shapes and their properties.