Quadrilateral Definition and Type of quadrilaterals

Quadrilaterals- a simple closed figure surrounded by four line segment is called a quadrilaterals. It has four sides , four angles, four vertices and two diagonals. The sum of all angles are 360^0.
Adjacent side- having a common end point. e.g PQ & QR
Opposite side- do not have any common point. eg. PQ, RS

Similarly the adjacent angles opposite angle.
The sum of the angle of a quadrilateral is 360^0 .

Type of quadrilaterals:
Rectangle– a quadrilateral in which opposite side are parallel & equal & each angle is 90^0 called a rectangle.

Area= L*B

Square– a rectangle in which all sides are equal opposite side are, parallel and each angle is 90^0, called a square.
Area= side^2

Parallelogram– a quadrilateral opposite sides are parallel & opposite angles are equal is called parallelogram.

Area=length of one side* perpendicular height
or \frac{1}{2}ac*bd (diagonals)
Perimiter=4* side

Rhombus– a quadrilateral which all side are equal , opposite side are parallel and opposite angles are equal is called rhombus.
Trapezium– a quadrilateral having one opposite side is parallel is called trapezium. When if its non parallel sides are equal is called isosceles trapezium. a quadrilateral is called if their adjacent sides are equal and opposite sides are unequal.


Area= 1/2(AB+CD)*H
Perimeter=Total of all sides