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Chapter 10 of 28
Important Questions

Isosceles Triangles

ICSE · Class 9 · Mathematics

Most important questions from Isosceles Triangles for ICSE Class 9 Mathematics board exam 2026. MCQs, short answer, and long answer questions with marks.

35 questions20 flashcards5 concepts

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A labeled diagram illustrating an isosceles triangle with two equal sides and the angles opposite to them also being equal. Includes the definition of an equilateral triangle as a special case.
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35 Questions·
multiple choicemultiple correcttext answertrue falsematchingordering

Sample Questions

1multiple correct

Which of the following statements are true for an isosceles triangle? (Select all correct options)

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It has at least two equal sides, Angles opposite to equal sides are equal, The altitude from vertex angle bisects the base

An isosceles triangle has at least two equal sides (not necessarily all three). The fundamental property is that angles opposite to equal sides are equal. The altitude from the vertex angle to the base bisects the base at right angles. A triangle cannot have two right angles as the sum would exceed 180°.

2text answer

If the vertex angle of an isosceles triangle is 120°, find each base angle.

3true false

True or False: In an isosceles triangle, the altitude, median, and angle bisector from the vertex angle to the base are the same line.

Show answer

True

This is true for isosceles triangles. The altitude from the vertex angle to the base also serves as the median (bisects the base), angle bisector (bisects the vertex angle), and perpendicular bisector of the base. This is a unique property of isosceles triangles.

4text answer

In triangle XYZ, XY = XZ = 15 cm and ∠YXZ = 80°. Calculate the perimeter if YZ = 18 cm.

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Frequently Asked Questions

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?
Understand the core concepts first, then work through the 35 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.
How many important questions are there in Isosceles Triangles?
There are 35 practice questions available for Isosceles Triangles. These cover multiple question types including MCQs, short answer, and long answer questions.

Sources & Official References

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

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