**Notes of chapter: Quadrilaterals are presented below. Indepth notes along with worksheets and NCERT Solutions.**

**(1) Plane surface-**

A surface which has no thickness and extends in all directions is called** plane surface**.

**Eg :-** Paper

**(2)Plane curve-**

A **plane curve** is a curve that can be obtained by joining a number of points and without retracing any portion of the drawing other than single points.

**Eg:-** Circle

**(3)Diagonal-**

A **diagonal **is a line segment connecting two non- consecutive vertices of a polygon.

**Eg:- **

**(i)**

**(4) Interior of a closed curve-**

The **interior of a closed curve** is an area inside the boundary of closed curve.

**Eg:-**

**(5) Exterior of a closed curve**

The **exterior of a closed curve** is an area outside the boundary of closed curve.

**Eg:-**

**(6)Polygons-**

**Polygons **are closed figures with straight line segments. These segments are called edges or sides. Their meeting points are called vertices.

**Eg:-** Triangle, square, parallelogram etc.

**Polygons**

**(7) Quadrilateral **

**Quadrilateral** is a polygon that has four sides and four vertices.

**Eg:- **Rectangle, square, kite etc.

All have four sides and four vertices.

**(8)** The **sum of angles of a quadrilateral** –

**(10)** **Types of Quadrilaterals**

**(i)** **Trapezium **

**(a)** It has four sides.

**(b)** It has a pair of parallel sides.

**Eg:-**

**(ii)Kite-**

**(a)** Kite has four sides.

**(b)** It has two distinct consecutive pairs of sides of equal length.

**(c)** Angles are equal between unequal straight lines.

**Eg:-**

**(iii) Parallelogram-**

**(a)** It has four sides.

**(b)**Its opposite sides are parallel and equal in length.

**(c)**The opposite angles of a parallelogram are of equal measure.

**(d)** The consecutive angles in a parallelogram are supplementary.

**(e)** The diagonals of a parallelogram bisect each other at the point of intersection.

**Eg:-**

**(iv) Rhombus**

**(a)** It is a quadrilateral with four sides of equal length.

**(b)** The diagonals of a rhombus are perpendicular bisectors of one another.

**(c)**Rhombus is a parallelogram but also has properties of kite.

**Eg:-**

**(v) Rectangle**

**(a)** It has four sides. Opposite sides are equal and parallel.

**(b)** Each angle of rectangle is right angle.

**(c)** Diagonals of the rectangle bisect each other and are equal in length.

**Eg:-**

**(vi) Square**

**(a)** It has all the properties of rectangle.

**(b)** The diagonals of a square are perpendicular bisectors of each other.

**Eg:-**

**Helping Topics**

**NCERT Solutions Class 8**

**NCERT Solutions Class 9**

**Worksheet Class 8**

**Worksheet Class 9**

### Like this:

Like Loading...