Types of Quadrilateral

The six quadrilaterals

A quadrilateral is any shape with four straight sides. There are six you meet again and again, each pinned down by one defining property:

a square has four equal sides and four right angles;
a rectangle has four right angles, with opposite sides equal;
a rhombus has four equal sides (a "pushed-over" square);
a parallelogram has both pairs of opposite sides parallel;
a trapezium has exactly one pair of parallel sides;
a kite has two pairs of adjacent equal sides.

Equal sides are shown with matching tick marks, parallel sides with matching arrowheads, and a right angle with a small square.

How they fit together

These shapes are not six separate boxes — the special ones are particular cases of the more general ones.

every quadrilateral's interior angles sum to 360^\circ;
a square is a special rectangle (it just also has equal sides) and a special rhombus (it just also has right angles);
a rectangle and a rhombus are both special parallelograms — once opposite sides are equal, they are automatically parallel.

Meet the family

Step through the gallery to see one of each, drawn with its defining marks. Watch how the marks change from shape to shape — they are exactly the property in each name.