# RS Aggarwal Chapter 10 Class 9 Maths Exercises 10.2 (ex 10b) Solutions

RD Sharma Chapter 10 Class 9 Maths Exercise 10.2 Solutions: You have studied many properties of a triangle in Chapters 6 and 7 and you know that on joining three non-collinear points in pairs, the figure so obtained is a triangle. Now, let us mark four points and see what we obtain on joining them in pairs in some order. Although most of the objects we see around are of the shape of a special quadrilateral called a rectangle, we shall study more about quadrilaterals and especially parallelograms because a rectangle is also a parallelogram and all properties of a parallelogram are true for a rectangle as well.

EXERCISE 10B

## Important Definition for RS Aggarwal Chapter 10 Class 9 Maths Ex 10b Solutions

A parallelogram is a type of quadrilateral that contains parallel opposite sides.

Area of parallelogram = Base × HeightArea of Triangle = (1/2)× Base × Height

Quadrilaterals- In this chapter, you will learn about a four-point closed figure. The figure formed by joining four points in order is called a quadrilateral. A quadrilateral has the following properties: Four sides, Four angles, and Four vertices.

The chapter begins by giving details about the Angle Sum Property of a Quadrilateral.

The sum of the angles of a quadrilateral is 360°.

Another Condition for a Quadrilateral to be a Parallelogram is explained.  A quadrilateral is a parallelogram if a pair of contrary sides are equal and parallel.
After this, the Mid-factor Theorem is discussed.
The line segment becoming a member of the mid-points of two aspects of a triangle is parallel to the third side.
A line via the midpoint of a triangle parallel to another side bisects the third side.

Two theorems are given in this section. A project for students is also given in which they learn the mid-point theorem.

While the definition states “parallelogram”, it is enough to say, “A quadrilateral is a rhombus if and only if it has 4 congruent sides”, considering any quadrilateral with four congruent aspects is a parallelogram.

Know more here.