RD Sharma Solutions for Class 7 Maths Chapter 18 Symmetry
By Ankit Gupta
|
Updated on 24 Apr 2025, 12:02 IST
Symmetry is all around us. From butterflies and leaves to buildings and art, we can see symmetry in many places in our daily life. In mathematics, symmetry is an important concept that helps us understand balance and beauty in shapes and patterns. Chapter 18 of the RD Sharma Class 7 Maths book introduces students to the basic ideas of symmetry in a very interesting way.
In this chapter, you will learn what symmetry means in geometry. When a shape is folded in half and both sides match exactly, it is called symmetrical. The line that divides the shape into two equal parts is called the line of symmetry. Some shapes have only one line of symmetry, while others may have many. For example, a square has four lines of symmetry, but a triangle may have only one or three depending on its type.
RD Sharma’s Chapter 18 focuses on line symmetry, helping students understand which shapes and figures have symmetry and how to draw or identify the lines of symmetry. It also gives you many examples, diagrams, and exercises that make the concept easy to grasp. The chapter not only teaches the definition and meaning of symmetry but also helps students improve their visual thinking and observation skills.
Do Check: RD Sharma Solutions for Class 7 Maths
To make learning more fun and simple, RD Sharma Solutions for Class 7 Chapter 18 provides detailed answers to all the textbook questions. These solutions are written step-by-step so that students can follow the logic easily. Whether it's matching figures, drawing lines of symmetry, or identifying symmetrical objects, the solutions help you practice and master the topic with confidence.
Using these RD Sharma solutions, students can clear their doubts quickly and understand how to approach different types of questions. These answers are helpful for homework, revisions, and exam preparation. The clear language and well-explained steps make them perfect for self-study.
Overall, Chapter 18 is a fun and visually engaging part of your Class 7 Maths journey. With the help of RD Sharma’s book and the easy-to-understand solutions, learning about symmetry becomes enjoyable and meaningful. So, let’s explore the world of symmetry and discover how maths connects to the patterns we see every day!
Download RD Sharma Solutions for Class 7 Maths Chapter 18 Symmetry PDF Here
RD Sharma Class 7 Chapter 18 PDF includes detailed solutions, examples, and extra questions to help you master real numbers and other topics. Click here to download the RD Sharma Class 7 Chapter 18 PDF.
Access Answers to RD Sharma Solutions for Class 7 Maths Chapter 18 Symmetry
In this chapter, students will learn about decimals and how to perform basic operations with them. The solutions provided here are detailed and easy to follow, helping students understand each concept thoroughly.
Q1. Mention how many lines of symmetry the following shapes have:
(i) Equilateral Triangle
An equilateral triangle has 3 lines of symmetry. These lines divide it into equal mirror halves.
(ii) Isosceles Triangle
An isosceles triangle has 1 line of symmetry. It goes from the top vertex to the midpoint of the base.
(iii) Scalene Triangle
A scalene triangle has 0 lines of symmetry because all its sides and angles are different.
(iv) Rectangle
A rectangle has 2 lines of symmetry – one vertical and one horizontal.
(v) Rhombus
A rhombus has 2 lines of symmetry along its diagonals.
(vi) Square
A square has 4 lines of symmetry – 2 along the diagonals and 2 along the midlines.
(vii) Parallelogram
A parallelogram does not have any line of symmetry.
(viii) General Quadrilateral
A general quadrilateral has 0 lines of symmetry.
(ix) Regular Pentagon
A regular pentagon has 5 lines of symmetry.
(x) Regular Hexagon
A regular hexagon has 6 lines of symmetry.
(xi) Circle
A circle has an unlimited number of symmetry lines – every diameter is a line of symmetry.
(xii) Semi-circle
A semi-circle has only 1 line of symmetry, which is a vertical line through the center.
Q2. Fill in the table with rotational properties of shapes:
| Shape | Centre of Rotation | Order of Rotation | Angle of Rotation |
| Square | Intersection of diagonals | 4 | 90° |
| Rectangle | Intersection of midlines | 2 | 180° |
| Rhombus | Intersection of diagonals | 2 | 180° |
| Equilateral Triangle | Centroid | 3 | 120° |
| Regular Hexagon | Center of hexagon | 6 | 60° |
| Circle | Center | Unlimited | Any angle |
| Semi-circle | None | None | None |
Q3. Complete the table for symmetry in English alphabets:
| Letter | Line Symmetry | Number of Lines of Symmetry | Rotational Symmetry | Order of Rotation |
| Z | No | 0 | Yes | 2 |
| S | No | 0 | Yes | 2 |
| H | Yes | 2 | Yes | 2 |
| O | Yes | 4 | Yes | 2 |
| E | Yes | 1 | No | 0 |
| N | No | 0 | Yes | 2 |
| C | Yes | 1 | No | 0 |
Q4. Name a shape that has no line of symmetry and no rotational symmetry:
A scalene triangle is an example of a shape with neither line symmetry nor rotational symmetry.
Q5. Name an English letter that:
(i) Has no line of symmetry: The letter Z.
(ii) Has rotational symmetry of order 2: The letter N.
Q6. Does a semi-circle have any line or rotational symmetry?
A semi-circle has only one line of symmetry, which is a vertical line that splits it in half. It does not have any rotational symmetry.
FAQS on RD Sharma Solutions for Class 7 Maths Chapter 18 Symmetry
What is Chapter 18 – Symmetry about in RD Sharma Class 7 Maths?
Chapter 18 explains the concept of symmetry in shapes and figures. It teaches students how to identify symmetrical figures and draw lines of symmetry. It focuses mainly on line symmetry in 2D shapes.
Why should I use RD Sharma Solutions for the Symmetry chapter?
RD Sharma Solutions provide step-by-step explanations for every question in the textbook. They help you understand the method clearly, making it easier to learn, revise, and prepare for exams.
How many exercises are there in Chapter 18 of RD Sharma Class 7 Maths?
Chapter 18 usually has 1 exercise with multiple questions based on lines of symmetry and symmetrical figures. The RD Sharma Solutions cover all questions in detail.
Are the RD Sharma Solutions for Chapter 18 helpful for exams?
Yes, they are very helpful. The solutions follow the textbook method, so they match what is taught in class. Practicing from them can help you score better in tests and exams.
Do the solutions include diagrams for better understanding?
Yes, most solutions include neat and clear diagrams that help you understand symmetry visually. These visuals make it easy to learn how to draw and identify lines of symmetry.
Can I use these solutions for quick revision before tests?
Absolutely! These solutions are written in a simple and easy-to-follow format. They are great for last-minute revisions and for clearing doubts quickly.
Are the RD Sharma Solutions available online for free?
Yes, many educational websites offer free access to RD Sharma Solutions, including the chapter on symmetry. You can easily read or download them to study anytime.