**Quadrilateral**s Definition

*Quadrilateral* is a geometric shape which has four sides and four vertices.

## Types of Quadrilaterals

- Trapezium
- Rhombus
- Parallelogram
- Square
- Rectangle

### TRAPEZIUM

- A Trapezium is a quadrilateral which has two parallel sides in either of the directions.

*Side 1” and “Side 2” are parallel* in above figures.

### Regular and Irregular Polygon

#### Definition of Regular Polygon

A quadrilateral is said to be regular Polygon if all angles are equal and all sides are equal.

Examples of Regular polygon are

- Square
- Equilateral Triangle
- Regular Pentagon
- Hexagon

#### Irregular Polygon

whereas in irregular polygon either the sides are not equal or the angles are not equal.

Examples of irregular polygon are

- Rectangle.- All the angles in rectangle are 90 degrees but only opposite sides are equal.

2. Isoceles or obtuse angled triangle etc.

### Angle Sum Property

Simply put sum of all the angles in a triangle is 180 degrees.

**How to find Interior angles of any quadrilateral ?**

Divide shape into equal triangles . See video below

Sum of measures of all exterior angles of polygon is 360 degrees.

Remember

##### Types and Properties of Quadrilateral

- Regular Trapezium
- Square
- Rectangle
- Parallelogram
- Rhombus
- Kite

Regular Trapezium – Trapezium is a quadrilateral with one pair of parallel sides.

Isoceles trapezium is one in which non parallel sides of trapezium are equal in length.

**Square **:

- All the four sides of square are equal.
- All the four angles are of 90 degrees.
- Opposite sides are parallel.
- Diagonals bisect each other at 90 deg.i.e perpendicular to each other.

**Rectangle : **–

- Opposite sides of rectangle are equal and Parallel.
- All the angles in rectangle are 90 degrees.
- Diagonals of rectangle are of equal length.

**Parallelogram : –**

- Opposite sides of parallelogram are equal and parallel.
- The diagonals do not bisect at 90 degrees.
- Opposite angles of parallelogram are equal by Angle side angle congruency.

**Rhombus :-**

- All sides are equal in rhombus.
- Diagonal bisect each other at 90 degrees.
- All sides are equal in rhombus.
- Opposite sides are parallel.

**Kite : –**

- Adjacent sides of kite are equal.
- Diagonals bisect at 90 degrees.

For any futher information or observations.please mark below.