# Notes Class 9 Mathematics Chapter 8 Quadrilaterals

Please refer to Quadrilaterals Class 9 Mathematics Notes and important questions below. The Class 9 Mathematics Chapter wise notes have been prepared based on the latest syllabus issued for the current academic year by CBSE. Students should revise these notes and go through important Class 9 Mathematics examination questions given below to obtain better marks in exams

## Quadrilaterals Class 9 Mathematics Notes and Questions

The below Class 9 Quadrilaterals notes have been designed by expert Mathematics teachers. These will help you a lot to understand all the important topics given in your NCERT Class 9 Mathematics textbook.

Refer to Chapter 8 Quadrilaterals Notes below which have been designed as per the latest syllabus issued by CBSE and will be very useful for upcoming examinations to help clear your concepts and get better marks in examinations.

• Angle Sum Property of a Quadrilateral
• Properties of a Parallelogram
• The Mid-Point Theorem
(1) Sum of the angles of a quadrilateral is 360o
(2) A diagonals of a parallelogram divides it into two congruent triangles.
(3) In a parallelogram
(a) diagonals bisect each other.
(b) opposite angles are equal.
(c) opposite sides are equal
(4) Diagonals of a square bisects each other at right angles and are equal, and vice-versa.
(5) A line through the mid-point of a side of a triangle parallel to another side bisects the third side. (mid-point theorem)
(6) The line through the mid points of sides of a D || to third side and half of it.
(7) A quadrilateral is a parallelogram, if
(a) its opposite angles are equal.
(b) its opposite sides are equal.
(c) its diagonals bisect each other.
(d) a pair of opposite sides is equal and parallel.
(8) Diagonals of a rectangle bisect each other and are equal and vice-versa.
(9) Diagonals of a rhombus bisect each other at right angles and vice-versa.
(10) A line through the mid-point of a side of a triangle parallel to another side bisects the third side.
(11) 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.