RS Aggarwal Solutions for Class 7 Maths Chapter 18–Reflection and Rotational Symmetry

Class 7: Maths Chapter 18 solutions. Complete Class 7 Maths Chapter 18 Notes.

RS Aggarwal Solutions for Class 7 Maths Chapter 18–Reflection and Rotational Symmetry

RS Aggarwal 7th Maths Chapter 18, Class 7 Maths Chapter 18 solutions

Ex 18A Solutions

Tick (✓) the correct answer in each of Q.1 to Q.9
Question 1.
Solution:
(a) A scalene triangle has no line of symmetry

Question 2.
Solution:
(c) A rectangle has two lines of symmetry which are the lines joining the mid points of opposite sides.

Question 3.
Solution:
(d) A square has four lines of symmetry which are two diagonal and two the lines joining the mid points of opposite sides.

Question 4.
Solution:
(b) A rhombus has two lines of symmetry which are the diagonals.

Question 5.
Solution:
(d) A circle has an unlimited number of lines of symmetry as its lines of symmetry is its diameter which are infinite in number.

Question 6.
Solution:
(a) ∆ABC in which AB = AC, is an isosceles triangle and AD ⊥ BC.

AD is the line of symmetry

Question 7.
Solution:
(a) ABCD is a kite in which AB = AD and BC = DC

Its line of symmetry will be one diagonal AC.

Question 8.
Solution:
(c) The letter O of the English Alphabet has two lines of symmetry as shown here in the figure.

Question 9.
Solution:
(a) The letter Z of the English Alphabet has no line of symmetry.

Question 10.
Solution:
The line/lines of symmetry have been drawn as given below :

Question 11.
Solution:
(i) True
(ii) True
(iii) True : The bisectors of angles are its lines of symmetry.
(iv) False : A rhombus has two lines of symmetry which are its diagonals.
(v) True : The two diagonals and two perpendicular bisector of its opposite sides are the lines of symmetry.
(vi) True : The perpendicular bisectors of opposite sides are the two lines of symmetry of the rectangle.
(vii) True : Each of the English Alphabet H, I, O and X has two lines of symmetry.

Ex 18B Solutions

Question 1.
Solution:
(a) An equilateral triangle has three lines of symmetry which are the angle bisectors.
(b) It has three order of rotational symmetry.

Question 2.
Solution:
The rectangle should be rotated through 180° and 360° to be in symmetrical position with the original position as given below :

Question 3.
Solution:
A square has four orders of rotational symmetry and angles through which the rotational symmetry are 90°, 180°, 270° and 360° as given below:

Question 4.
Solution:
(i) A rhombus has two lines of symmetry which are its diagonal.
(ii) Order of rotational symmetry of a rhombus is not possible. Therefore it has no rotational symmetry.

Question 5.
Solution:
Three letters of the English Alphabet which have two lines of symmetry and rotational symmetry of order 2 are H, I and N.

Question 6.
Solution:
The figure which has only on line of symmetry but no rotational symmetry order is an isosceles triangle.

Question 7.
Solution:
No, only isosceles trapezium has a line of symmetry but not every trapezium.

Question 8.
Solution:
The line of symmetry of a semicircle is the perpendicular bisector of the diameter No, it has not any rotational symmetry.

Question 9.
Solution:
A scalene triangle has neither any line of symmetry nor a rotational symmetry.

Question 10.
Solution:
In the given figure, the line of symmetry has been drawn which is one. There is no rotational symmetry of this figure.

Question 11.
Solution:
(i) The given figure has two lines of symmetry which has been drawn.

(ii) It has three orders of the rotational symmetry which are 90°, 270° and 360°.

Question 12.
Solution:
There is one letter of the English Alphabet Z which has no line of symmetry but it has order two of rotational symmetry of 180° and 360°.

RS Aggarwal Solutions for Class 7 Maths Chapter 18: Download PDF

RS Aggarwal Solutions for Class 7 Maths Chapter 18–Reflection and Rotational Symmetry

Download PDF: RS Aggarwal Solutions for Class 7 Maths Chapter 18–Reflection and Rotational Symmetry PDF

Chapterwise RS Aggarwal Solutions for Class 7 Maths :

• Chapter 1–Integers
• Chapter 2–Fractions
• Chapter 3–Decimals
• Chapter 4–Rational Numbers
• Chapter 5–Exponents
• Chapter 6–Algebraic Expressions
• Chapter 7–Linear Equations in One Variable
• Chapter 8–Ratio and Proportion
• Chapter 9–Unitary Method
• Chapter 10–Percentage
• Chapter 11–Profit and Loss
• Chapter 12–Simple Interest
• Chapter 13–Lines and Angles
• Chapter 14–Properties of Parallel Lines
• Chapter 15–Properties of Triangles
• Chapter 16–Congruence
• Chapter 17–Constructions
• Chapter 18–Reflection and Rotational Symmetry
• Chapter 19–Three-Dimensional Shapes
• Chapter 20–Mensuration
• Chapter 21–Collection and Organisation of Data (Mean, Median and Mode)
• Chapter 22–Bar Graphs
• Chapter 23–Probability

About RS Aggarwal Class 7 Book

Investing in an R.S. Aggarwal book will never be of waste since you can use the book to prepare for various competitive exams as well. RS Aggarwal is one of the most prominent books with an endless number of problems. R.S. Aggarwal’s book very neatly explains every derivation, formula, and question in a very consolidated manner. It has tonnes of examples, practice questions, and solutions even for the NCERT questions.

He was born on January 2, 1946 in a village of Delhi. He graduated from Kirori Mal College, University of Delhi. After completing his M.Sc. in Mathematics in 1969, he joined N.A.S. College, Meerut, as a lecturer. In 1976, he was awarded a fellowship for 3 years and joined the University of Delhi for his Ph.D. Thereafter, he was promoted as a reader in N.A.S. College, Meerut. In 1999, he joined M.M.H. College, Ghaziabad, as a reader and took voluntary retirement in 2003. He has authored more than 75 titles ranging from Nursery to M. Sc. He has also written books for competitive examinations right from the clerical grade to the I.A.S. level.

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