Chapter 9 Class 6 - Symmetry (Ganita Prakash)

Master Chapter 9 Class 6 - Symmetry (Ganita Prakash) with comprehensive NCERT Solutions, Practice Questions, MCQs, Sample Papers, Case Based Questions, and Video lessons.

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Definition

Line of symmetry

Figures with more than one line of symmetry

Reflection Symmetry

Generating shapes having lines of symmetry

Figure it out - Page 224 - 229

Rotational Symmetry

Figure it out - Page 235

Questions - Page 236

Symmetries of a Circle

Figure it out - Page 238, 239

Why Learn This With Teachoo?

Welcome to Chapter 9, Symmetry, from your Class 6 Maths book, Ganita Prakash.

Have you ever noticed why a butterfly's wings look so perfect? Or why a flower or a rangoli design is so pleasing to look at? Often, the secret is symmetry.

Symmetry is a concept that we see all around us in nature, art, and architecture. It refers to a balanced and proportionate structure, where parts of a figure are repeated in a definite pattern. This chapter is a fascinating exploration of these patterns and the rules that govern them.


 

What We Will Study in This Chapter

 

This chapter will introduce you to the two main types of symmetry and how to identify and create them.

 

1. Line Symmetry (Reflection Symmetry)

 

This is the most common type of symmetry, often called mirror symmetry.

  • What it is: A shape has line symmetry if it can be folded along a line so that one-half of the figure fits exactly on top of the other half.

  • Line of Symmetry: This fold line is called the line of symmetry.

  • Exploring Lines: We will discover that figures can have:

    • One line of symmetry (like a butterfly).

    • Multiple lines of symmetry (a square has four!).

    • No lines of symmetry at all (like a picture of a cloud).

  • Hands-on Creation: You will learn to create your own symmetrical figures using fun activities like inkblot devils, paper folding and cutting, and punching holes in folded paper.

 

2. Rotational Symmetry

 

Sometimes, a shape is symmetrical, but you can't find a fold line that works. A pinwheel is a perfect example.

  • What it is: A shape has rotational symmetry if it looks exactly the same after being rotated (or turned) around a fixed point by an angle less than a full $360^{\circ}$ turn.

  • Centre and Angle: You will learn to identify the centre of rotation (the fixed point you turn it around) and the angle of rotational symmetry (the smallest angle you need to turn it). For example, a square looks the same after a $90^{\circ}$ turn.

  • Order of Rotation: We will also learn to find the "order" of rotational symmetry, which is how many times a shape looks the same during one full rotation.

This chapter will teach you to see the hidden mathematical structure in the world around you. It's a very visual and hands-on topic, and at Teachoo, we'll guide you through every step, from finding lines of symmetry to understanding the angles of rotation.

To get started, please click on any topic link.