(i) Parallelogram: A quadrilateral in which opposite sides are parallel is called parallelogram and it is written as Parallelogram.
(ii) Rectangle: A parallelogram each of whose angle is 90°, is called a rectangle.
(iii) Square: A rectangle having all sides equal, is called a square.
(iv) Rhombus: A parallelogram having all sides equal is called a rhombus.
(v) Trapezium: A quadrilateral in which two opposite sides are parallel and two opposite sides are non-parallel is called a trapezium.
If two non-parallel sides of a trapezium are equal, then it is called an isosceles trapezium.
(vi) Kite: A quadrilateral in which two pairs of adjacent are equal is known as the kite.