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 .

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 .

**Type of quadrilaterals**:

**Rectangle**– a quadrilateral in which opposite side are parallel & equal & each angle is called a rectangle.

**Square**– a rectangle in which all sides are equal opposite side are, parallel and each angle is , called a square.

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

or (diagonals)

**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.

**Trapezoid**: