Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

RS Aggarwal Class 9 Solutions Chapter-8 Triangles

ffImage
banner

Class 9 RS Aggarwal Chapter-8 Triangles Solutions - Free PDF Download

Any planar structure that consists of three sides and three vertices is called a triangle. According to Euclidean geometry, any three non-collinear points form a triangle. Triangle is a planar figure with two dimensions.

Competitive Exams after 12th Science
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow

Properties of a Triangle:

  • The Perimeter of a Triangle: ½ × Length × Breadth.

  • Area of a Triangle: Total sum of the lengths of a triangle.

  • Internal Angle: 60°.

  • Total Sum Internal Angles: 180°.

 

Types of Triangles:

Triangles can be distinguished on the following basis:

  • According to the length of the sides

  • According to the measure of internal angles 

  • According to the Length of Sides:

  1. Equilateral Triangle: It is a Triangle with all sides of the same length. All the internal angles are 60°. Let us suppose a Triangle of sides a, b and c

Equilateral Triangle: a = b = c

  1. Isosceles Triangle: It has two sides of equal length and another side is of different measure.

Isosceles Triangle: a = b but not equal to c

  1. Scalene Triangle: It has sides of unequal length which means all the sides are of different lengths. All the angles are also of different lengths.

 

  • According to the measure of internal angles:

1. Right Angle Triangle: Any triangle with one interior angle of measure 90° is known as Right Triangle.

 

            Right angles obey Pythagoras Theorem which is a2 + b2 = c2

 

Where a, b, c are the sides of any Triangle

 

2. Obtuse Triangle: Any triangle with anyone interior angle greater than 90° is called an obtuse triangle.

 

3. Acute Triangle: Any triangle with interior angles less than 90° is called Acute  Triangle.

 

Let us now work on a few examples related to Triangle problems:

Problem 1: Consider a triangle with sides 3 cm, 6 cm, and 10 cm then find the perimeter of the triangle.

Ans: Perimeter of a Triangle = a + b + c

 

        Perimeter = 3 + 6 + 10

 

   = 19cm

 

Many questions based on Heron's Formula are asked in various examinations. So, let us study this very important formula.

 

We apply Heron's formula when we are asked to find the area of the Triangle but we are not provided with the height of the Triangle. In that case, we can easily solve the problem by using Heron's Formula.

 

We can solve the problem using Heron's Formula provided that all the sides of the triangle are given in the question.

 

Area of Triangle using Heron's Formula=

 

√s(sa)(sb)(sc)

 

√s(s−a)(s−b)(s−c)

 

Here, a, b, c are sides of Triangle

 

And   s = (a + b + c)/2

 

Let’s solve a problem based on the above concept.

 

Problem 2: Determine the area of a triangle with sides 4, 6, and 8 units in length.

Answer: As we are not given the height of the Triangle so, we have to use Heron's Formula to determine the area of the Triangle 

 

Semi perimeter(s)= a + b + c/2

 

                                = 4 + 6 + 8/2 = 9

 

Now Area of Triangle= √

 

s(sa)(sb)(sc)

 

s(s−a)(s−b)(s−c)

 

=√9(9−5)(9−4)(9−8)

 

√9(9−5)(9−4)(9−8)

 

=√9×4×5×1

 

√9×4×5×1

 

=√3×3×2×2×5

 

√3×3×2×2×5

 

= 6√5 square units 

 

RS Aggarwal Class 9 solutions chapter 8 triangles consist of an exercise named Exercise 8 with a total of 29 questions. After that, there are Multiple Choice Questions which are 12 in all.


RS Aggarwal Class 9 Solutions Chapter 8: Preparation Tips

Class 9 math RS Aggarwal chapter 8 solutions can be solved with an easy method. Students are advised to go through all the basic concepts related to Chapter-8 of Class 9 which will further help them to understand the solutions given by RS Aggarwal more easily. We advise the child to first solve simple and easy questions. When they can solve such questions only then they should try their hands for solutions to tough questions in RS Aggarwal. They should revise the same concept after a particular period to strengthen their learning power.

 

No doubt Triangle seems to be an easy topic but sometimes questions are confusing and students find themselves solving such questions.RS Aggarwal solutions class 9 math chapter 8 are compiled in such a manner that they cover various concepts. Students should thoroughly follow every solution of RS Aggarwal solutions class 9 math ch 8 to be able to solve the toughest questions.

 

Scoring well in your exam is now easy with the help of RS Aggarwal Class 9 Solutions Chapter 8 Triangles. Vedantu has put in their efforts to produce an RS Aggarwal Class 9 Solutions Chapter-8 Triangles that will help you out with the solving of various questions associated with Chapter 8. With an easy language used in the Solutions by RS Aggarwal,it provides a chance for students to understand all the topics by themselves. This Chapter 8 Triangle provides an idea about the variety of sides and angles that a triangle possesses and who there are a variety of triangles and just one type.


Advantages of using RS Aggarwal Class 9 Solutions Chapter 8 Triangles:

RS Aggarwal Class 9 Solutions Chapter 8 Triangles is considered to be a wonderful resource for students of Class 9 who are in search of solutions that will clear them of the difficult concepts and doubts that arise while studying the topic.


RS Aggarwal Class 9 Solutions Chapter 8 Triangles by Vedantu also helps improve their skills when it comes to problem-solving and finding out the answers to a question on their own. The students also get a chance to learn and capture different ideas and formulae effectively while managing their time efficiently.

WhatsApp Banner
Best Seller - Grade 11 - JEE
View More>
Previous
Next

FAQs on RS Aggarwal Class 9 Solutions Chapter-8 Triangles

1. How do RS Aggarwal Solutions for Class 9 Maths Chapter 8 help with difficult triangle problems?

Vedantu's RS Aggarwal Solutions for Class 9 Maths Chapter 8 help by breaking down complex problems into simple, understandable steps. They provide detailed explanations for each theorem and proof, focusing on the correct methodology as per the CBSE 2025-26 guidelines. This approach helps you identify the appropriate congruence rule or property needed to solve even the most challenging questions.

2. What are the main congruence criteria for triangles covered in RS Aggarwal Class 9 Chapter 8?

The primary criteria for proving the congruence of triangles in this chapter are:

  • SAS (Side-Angle-Side): Two sides and the included angle of one triangle are equal to the corresponding sides and included angle of the other.
  • ASA (Angle-Side-Angle): Two angles and the included side of one triangle are equal to the corresponding angles and included side of the other.
  • AAS (Angle-Angle-Side): Two angles and a non-included side of one triangle are equal to the corresponding angles and non-included side of the other.
  • SSS (Side-Side-Side): All three sides of one triangle are equal to the corresponding three sides of the other.
  • RHS (Right-angle-Hypotenuse-Side): In two right-angled triangles, the hypotenuse and one side of one triangle are equal to the hypotenuse and corresponding side of the other.

3. What is the difference between the ASA and AAS congruence rules, and how do you decide which one to use?

The key difference lies in the position of the side. In the ASA (Angle-Side-Angle) rule, the side must be the included side, meaning it is located between the two angles. In the AAS (Angle-Angle-Side) rule, the side is a non-included side. You can use AAS when you know two angles and a side that is not between them. Essentially, if you know any two angles of a triangle, you can find the third, which often allows you to convert an AAS situation into an ASA one.

4. When applying the SAS congruence rule, what is the most common mistake students make?

The most common mistake when using the SAS (Side-Angle-Side) rule is failing to ensure the angle is the included angle. For this rule to be valid, the angle you are using for comparison must be the one formed by the two sides you are comparing. For instance, to prove ∆ABC ≅ ∆PQR using SAS with sides AB=PQ and BC=QR, you must prove that ∠B = ∠Q, as it is the angle between the given sides.

5. Why is the RHS congruence criterion only applicable to right-angled triangles?

The RHS criterion is specific to right-angled triangles because its components are defined by them. 'R' stands for a Right angle (90°), and 'H' stands for the Hypotenuse, which is the side opposite the right angle. This unique combination of a 90° angle, the longest side (hypotenuse), and one other corresponding side provides enough information to guarantee congruence. This specific set of conditions does not ensure congruence in non-right-angled triangles.

6. How do you prove that the angles opposite to equal sides of a triangle are equal?

To prove this theorem for a triangle ABC where AB = AC, you can follow these steps:

  • First, draw an angle bisector of ∠A that meets the side BC at a point D.
  • Now, consider the two triangles formed: ΔABD and ΔACD.
  • You have AB = AC (given).
  • ∠BAD = ∠CAD (by construction, as AD is the angle bisector).
  • AD = AD (common side).
  • Therefore, by the SAS congruence rule, ΔABD ≅ ΔACD.
  • Since the triangles are congruent, their corresponding parts are equal. Hence, ∠ABD = ∠ACD, which means ∠B = ∠C.

7. Where can I find reliable, step-by-step solutions for all exercises in RS Aggarwal Class 9 Chapter 8?

Vedantu provides comprehensive, step-by-step solutions for all exercises in RS Aggarwal Class 9 Chapter 8, Triangles. These solutions are prepared by subject matter experts to ensure accuracy and adherence to the CBSE 2025-26 syllabus. Each answer explains the logic and method, making it easier for students to prepare for exams and clarify their doubts effectively.