Chapter 2 : Triangles - CBSE Class 9 Maths
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Chapter 2 : Triangles

Chapter 2 : Triangles

Triangles are fundamental geometric shapes characterized by three sides, three angles, and three vertices. Congruent triangles possess identical sizes and shapes, established through several congruence criteria including SSS, SAS, ASA, AAS, and RHS. This chapter also delves into triangle properties and inequalities, providing essential insights into the relationships between triangle sides and angles.

10 sections

Sections

Navigate through the learning materials and practice exercises.

  1. 7

    This section covers the fundamental properties of triangles, including types...

  2. 7.1

    This section defines triangles, outlines congruence criteria, and discusses...

  3. 7.2
    Congruence Criteria

    The section discusses the definition of congruent triangles and the various...

  4. 7.2.1
    Sss (Side-Side-Side)

    This section covers the SSS criterion for triangle congruence, defining...

  5. 7.2.2
    Sas (Side-Angle-Side)

    This section discusses the SAS congruence criterion for triangles, which...

  6. 7.2.3
    Asa (Angle-Side-Angle)

    The ASA (Angle-Side-Angle) theorem states that two triangles are congruent...

  7. 7.2.4
    Aas (Angle-Angle-Side)

    The AAS criterion states that if two angles and a non-included side of one...

  8. 7.2.5
    Rhs (Right Angle-Hypotenuse-Side)

    The RHS criterion is a method to prove the congruence of right triangles by...

  9. 7.3
    Properties Of A Triangle

    This section covers the fundamental properties of triangles, including...

  10. 7.4
    Inequalities In A Triangle

    Inequalities in a triangle refer to the relationships between the lengths of...

What we have learnt

  • A triangle consists of three sides, three angles, and three vertices.
  • Congruence criteria for triangles include SSS, SAS, ASA, AAS, and RHS.
  • Properties of triangles reveal relationships between angles and opposite sides.
  • Inequalities in triangles show that the larger angle is opposite the longer side.

Key Concepts

-- Congruent Triangles
Triangles that have the same size and shape.
-- Congruence Criteria
Rules used to determine if two triangles are congruent, including SSS, SAS, ASA, AAS, and RHS.
-- Triangle Inequalities
Principles stating that in a triangle, the greater angle is opposite the longer side and the sum of any two sides must be greater than the third side.
-- Properties of a Triangle
Characteristics such as equal angles opposite equal sides.

Additional Learning Materials

Supplementary resources to enhance your learning experience.