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Chapter 9 of 28
Syllabus

Triangles

ICSE · Class 9 · Mathematics

Complete topic list for Triangles in ICSE Class 9 Mathematics. Key concepts, sub-topics, and what to focus on for board exams.

45 questions25 flashcards5 concepts
4 Topics · ICSE Class 9 Mathematics

Topics in Triangles

1

Introduction and Basic Properties

  • A triangle is a plane figure bounded by three straight line segments
  • Every triangle has three vertices, three sides, and three angles
  • The sum of all angles in any triangle is always 180°
2

Relationship Between Sides and Angles

  • In a triangle with unequal sides, the greater side has the greater angle opposite to it
  • In a triangle with unequal angles, the greater angle has the greater side opposite to it
  • If two sides are equal, their opposite angles are also equal (isosceles triangle property)
3

Median and Altitude

  • A median joins a vertex to the midpoint of the opposite side
  • Every triangle has three medians that intersect at the centroid
  • The centroid divides each median in the ratio 2:1
4

Congruent Triangles

  • Two triangles are congruent if they have the same shape and size
  • Congruent triangles can be superimposed exactly on each other
  • Corresponding parts of congruent triangles are equal (CPCTC)

Key Concepts

A triangle has three verticesIn a triangleA median connects a vertexAn altitude is the perpendicular fromTwo triangles are congruent if they

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Frequently Asked Questions

What are the important topics in Triangles for ICSE Class 9 Mathematics?

Triangles covers several key topics that are frequently asked in ICSE Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.

Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.