A four-sided shape is a quadrilateral. With only one pair of parallel sides, it would be called a trapezoid (UK trapezium).
Any plane polygon having four or more sides may have one pair of parallel sides.
I am a quadrilateral, I have 4 vertices, I only have one pair of parallel sides, and I am also a polygon. What am I?
A four-sided polygon with opposite sides parallel could be a square, a rectangle, or a rhombus.If it has one pair of opposite, parallel sides, then it is a trapezoid. If it has two pairs of opposite, parallel sides, then it is a parallelogram.
A trapezoid has only one pair of parallel sides. These parallel sides are opposite and are of different lengths.
Trapezoid
A polygon with 4 or more sides can have a pair of parallel sides.
quadrilateral
polygon
A circle intersected by a pair of parallel lines.
A kite for example.
It is a deltoid or a kite.
A four-sided shape is a quadrilateral. With only one pair of parallel sides, it would be called a trapezoid (UK trapezium).
A trapezoid is not a parallelogram, a trapezoid is a polygon. The definition of parallelogram is a shape in which all sides are parallel. In a trapezoid, only one pair of sides is parallel.
diamond trapezium
Any polygon with four or more sides can have a pair of parallel sides. It is also possible to to have non-polygonal shapes - eg a cigar-shape - that has parallel sides.
Any plane polygon having four or more sides may have one pair of parallel sides.