NCERT Solutions for Class 9 Maths Chapter 8 Exercise 8.2

About Class 9 Maths Chapter 8 Quadrilaterals

We have seen that in a parallel quadrilateral, each pair of opposite sides is equal. Further, we also know that if each pair of opposite sides of the quadrilateral is equal, then it is a parallel quadrilateral. We can conclude the same result for couples of opposite angles that in the parallelogram, the opposite angles are the same. We have studied many properties of a parallel quadrilateral in Grade 9 Math Chapter 8. Here, we can say that a quadrilateral is a parallelogram if a pair of opposite sides are equal and parallel.

Properties of Quadrilaterals

We have studied many properties of a triangle and a quadrilateral. Now let’s examine another result that is related to the midpoint of the sides of a triangle. Do the following activity. Draw a triangle and mark the midpoints E and F of the two sides of the triangle. Join the points E and F. We will see that the line segment joining the midpoint of two sides of the triangle is parallel to the third side.

Significant result based on Mathematics chapter 8 from class 9

1. The sum of the angles of a quadrilateral is 360°.
2. The diagonal of a parallelogram divides it into two congruent triangles.
3. The diagonals of a rectangle intersect and are equal and vice versa.
4. The diagonals of an equilateral intersect at each other and vice versa.
5. The diagonals of a square cut each other at right angles and are equal, and vice versa.
6. The line segment joining the midpoints of any two sides of a triangle is parallel to the third side and half.
7. A line that passes parallel to one side of a triangle through the middle divides the third arm.
8. A quadrilateral formed by connecting the midpoints of a quadrilateral’s sides, in order, is a parallelogram.