A QUADRILATERAL is a four sided polygon. A property unique to quadrilaterals is that they can have parallel opposite sides (have the same continuous distance between them).
A trapezoid is a type of quadrilateral with only one set of parallel sides.
A parallelogram is a type of quadrilateral whose two pairs of opposite sides are parallel, and as a result, the opposite sides are of equal length. Squares, rectangles, and rhombi are all parallelograms since their opposite sides are parallel.
A rectangle is a type of parallelogram whose sides are perpendicular or meet at 90° angles.
A square is a special type of rectangle whose sides are all of equal length.
A rhomboid is a type of parallelogram whose sides do not meet at 90°.
A rhombus is a special type of rhomboid whose sides are all of equal length.
Square
Rectangle
Rhombus
Rhomboid
A Lesson in Geometry