Plane (two-dimensional) figure with four straight sides. The sum of all interior angles is 360°. The following are all quadrilaterals, each with distinguishing properties:
square with four equal angles and sides, and four axes of
symmetry;
rectangle with four equal angles, opposite sides equal, and two axes of symmetry;
rhombus with four equal sides, and two axes of symmetry;
parallelogram with two pairs of parallel sides, and rotational symmetry;
kite with two pairs of adjacent equal sides, and one axis of symmetry; and
trapezium with one pair of parallel sides.
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