Skip to main content
Chapter 20 of 25
Revision Notes

Symmetry (Including Reflection and Rotation)

ICSE · Class 8 · Mathematics

Quick revision notes for Symmetry (Including Reflection and Rotation) — ICSE Class 8 Mathematics. Key concepts, formulas, and definitions for last-minute revision.

47 questions30 flashcards5 concepts

Interactive on Super Tutor

Studying Symmetry (Including Reflection and Rotation)? Get the full interactive chapter.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for revision notes and more.

1,000+ Class 8 students started this chapter today

Key Topics to Revise

1

1. Symmetry and Line of Symmetry

  • A plane figure has symmetry if folding it about a line makes the two parts match exactly.
  • The line about which the figure is symmetrical is called a line of symmetry, axis of symmetry, or mirror line.
  • If a figure is symmetrical, points on one side match points on the other side at equal distances from the mirror line.
2

2. Symmetry in Common Figures

  • A line segment is symmetrical about its perpendicular bisector.
  • An angle with equal arms is symmetrical about its bisector.
  • An isosceles triangle is symmetrical about the bisector of the angle at the vertex.
3

3. Reflection of a Point in Coordinate Axes and Origin

  • When a point is reflected in the x-axis, only the sign of the y-coordinate changes.
  • When a point is reflected in the y-axis, only the sign of the x-coordinate changes.
  • When a point is reflected in the origin, both x and y signs change.
4

4. Rotation About the Origin

  • Rotation through 180° about the origin changes both signs of the coordinates.
  • Rotation through 90° anticlockwise and 90° clockwise have different coordinate rules.
  • A point rotated through 90° anticlockwise moves to a new position with coordinates based on the rule P'(-y, x).

Get complete notes with diagrams and examples

Full Notes

Key Concepts

A plane figure is symmetrical ifA line segment is symmetrical aboutA rectangle and a rhombus eachAny line passing through the centreWhen a point P(x

Frequently Asked Questions

What are the important topics in Symmetry (Including Reflection and Rotation) for ICSE Class 8 Mathematics?
Symmetry (Including Reflection and Rotation) covers several key topics that are frequently asked in ICSE Class 8 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in Symmetry (Including Reflection and Rotation) — ICSE Class 8 Mathematics?
Understand the core concepts first, then work through the 47 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.

Sources & Official References

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

For serious students

Get the full Symmetry (Including Reflection and Rotation) chapter — for free.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for ICSE Class 8 Mathematics.