Chapter 8 (Quadrilaterals) of Class 9 Maths NCERT Book in PDF format. You will get here the latest edition of the chapter for the current academic session 2021-2022. This chapter is important for class 9 annual exams. We have also provided here the best NCERT Solutions for the chapter that will help you find accurate and easy solutions for the questions given in the chapter. Also, solve the important questions given at the end of the article to prepare for the Maths tests/exams.
About Class 9 Maths Chapter 8 Quadrilaterals
Chapter 8 - Quadrilaterals of Class 9 Maths Book introduces students to quadrilaterals. It explains various types of quadrilaterals and discusses their properties.
Major topics discussed in the chapter are:
→ Introduction of Quadrilaterals
→ Angle Sum Property of a Quadrilateral
→ Types of Quadrilaterals
→ Properties of a Parallelogram
→ Condition for a Quadrilateral to be a Parallelogram
→ The Mid-point Theorem
A screenshot of the NCERT Class 9 Maths Chapter 8 is given below:
PDF download of the chapter can be accessed from the following link:
Some important points to revise from the chapter are:
• Sum of the angles of a quadrilateral is 360°.
• A diagonal of a parallelogram divides it into two congruent triangles.
• In a parallelogram,
(i) opposite sides are equal
(ii) opposite angles are equal
(iii) diagonals bisect each other
• A quadrilateral is a parallelogram, if
(i) opposite sides are equal or
(ii) opposite angles are equal or
(iii) diagonals bisect each other or
(iv) a pair of opposite sides is equal and parallel
• The line-segment joining the mid-points of any two sides of a triangle is parallel to the third side and is half of it.
• A line through the mid-point of a side of a triangle parallel to another side bisects the third side.
Download the NCERT Solutions for Class 9 Maths Chapter 8 from the following link:
Try some important questions given below for self-assessment:
1. Prove that the straight line joining the midpoint of the diagonals of a trapezium is parallel to the parallel sides and is equal to half their difference.
2. In the given figure, D, E and F are mid-points of the sides BC, CA and AB of △ABC. If AB = 4.3 CM, BC = 5.6 cm and AC = 3.6 cm, find the perimeter of △DEF.
3. In a parallelogram ABCD, E and F are points on AB and CD such that AE = CE. Prove that ED II BF.
4. AD is a median of △ABC and E is the mid-point of AD. BE produced meets AC in F, Prove that AF = 1/3 AC.
5. Show that the bisectors of angles of a parallelogram form a rectangle.