Isosceles Triangles
ICSE · Class 9 · Mathematics
Complete topic list for Isosceles Triangles in ICSE Class 9 Mathematics. Key concepts, sub-topics, and what to focus on for board exams.
Topics in Isosceles Triangles
Basic Definitions and Introduction
- An isosceles triangle has at least two equal sides
- An equilateral triangle is a special case of isosceles triangle where all three sides are equal
- In an isosceles triangle, the equal sides are called arms and the third side is called the base
Theorem 1: Equal Sides → Equal Angles
- If two sides of a triangle are equal, then angles opposite to them are also equal
- This is the fundamental property of isosceles triangles
- Proof uses construction of perpendicular from vertex to base
Theorem 2: Equal Angles → Equal Sides
- If two angles of a triangle are equal, then sides opposite to them are also equal
- This is the converse of Theorem 1
- Proof uses construction of perpendicular from vertex to base
Properties and Important Results
- The angle bisector from vertex of isosceles triangle bisects the base at right angles
- The perpendicular bisector of base passes through the vertex
- The line joining midpoint of base to vertex is perpendicular to base and bisects vertex angle
Key Concepts
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What are the important topics in Isosceles Triangles for ICSE Class 9 Mathematics?
Isosceles 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.
How to score full marks in Isosceles Triangles — ICSE Class 9 Mathematics?
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.
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