# Symmetry Class-8 RS Aggarwal ICSE Maths Goyal Brothers

Symmetry Class-8 RS Aggarwal ICSE Maths Goyal Brothers Prakashan Solutions Chapter-20. We provide step by step Solutions of Exercise / lesson-20 Symmetry for ICSE Class-8  RS   Aggarwal Maths.

Our Solutions contain all type Questions of Exe-20 with Notes to develop skill and confidence. Visit official Website CISCE for detail information about ICSE Board Class-8 Mathematics.

## Symmetry Class-8 RS Aggarwal ICSE Maths Goyal Brothers Prakashan Solutions Chapter-20

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Notes on Symmetry

Exe-20

### Notes on Symmetry

Symmetry is defined as a balanced and a proportionate similarity which is found in two halves of an object, that is, one-half is the mirror image of the other half. The imaginary line or axis along which you can fold a figure to obtain the symmetrical halves is called the line of symmetry

### Line of Symmetry

The imaginary line or axis along which you fold a figure to obtain the symmetrical halves is called the line of symmetry. It basically divides an object into two mirror-image halves. The line of symmetry can be vertical, horizontal or diagonal. There may be one or more lines of symmetry

### Types of Symmetry

Symmetry may be viewed when you flip, slide or turn an object. There are types of Symmetry which are:

• Reflexive
• Rotational Symmetry

Reflective or Line: A figure is symmetrical about a dotted line which divides it into two equal halves. This is often referred to as the basic type.

Rotational Symmetry: You rotate a shape about an axis and it appears exactly the same as it did before rotation. Example: a square, a rectangle, etc

Rotation, like the movement of the hands of a clock, is called a clockwise rotation; otherwise, it is said to be anticlockwise

A number of other kinds of symmetric types exist such as the point, translational, glide reflectional, helical, etc

## Lines of Symmetry for Regular Polygons

Regular polygons have equal sides and equal angles. They have multiple (i.e., more than one) lines of symmetry. Each regular polygon has as many lines of symmetry as it has sides.

 Regular Polygon Regular Hexagon Regular Pentagon Square Equilateral Triangle Number of Lines of Symmetry 6 5 4 3

Lines of Symmetry of some Irregular Polygons.

### Lines of Symmetry of some Alphabet

Each of the following capital letters of the English alphabet is symmetrical about the dotted line or lines as shown:

### Lines of Symmetry of some regular Polygons.

In a complete turn (of 360°), the number of times an object looks exactly the same is called the order of rotational symmetry.

### Exe-20, Symmetry Class-8 RS Aggarwal ICSE Maths Goyal Brothers Prakashan Solutions

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