Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry

Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry (Including Reflection and Rotation)

Selina Publishers Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry (Including Reflection and Rotation)

Symmetry Exercise 17A – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
For each figure, given below, draw the line (s) of symmetry, if possible :
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A Q1
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A Q1.1

Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 1

Question 2.
Write capital letters A to Z of English alphabet ; and in each case, if possible, draw the largest number of lines of symmetry.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 2
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 3

Question 3.
By drawing a free hand sketch of each of the following, draw in each case, the line (s) of symmetry,
if any:
(i) a scalene triangle
(ii) an isosceles right angled triangle
(iii) a rhombus
(iv) a kite shaped figure triangle.
(v) a rectangle
(vi) a square
(vii) an isosceles
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 4

Question 4.
Draw a triangle with :
(i) no line of symmetry,
(ii) only one line of symmetry,
(iii) exactly two lines of symmetry,
(iv) exactly three lines of symmetry,
(v) more than three lines of symmetry.
In each case, if possible, represent the line/ lines of symmetry by dotted lines. Also, write the special name of the triangle drawn.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 5

Question 5.
Draw a quadrilateral with :
(i) no line of symmetry.
(ii) only one line of symmetry.
(iii) exactly two lines of symmetry.
(iv) exactly three lines of symmetry.
(v) exactly four lines of symmetry.
(vi) more than four lines of symmetry.
In each case, if possible, represent the line/ lines of symmetry by dotted lines. Also, write the special name of the quadrilateral drawn.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 6
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 7

Question 6.
Construct an equilateral triangle with each side 6 cm. In the triangle drawn, draw all the possible lines of symmetry.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 8

Question 7.
Construct a triangle ABC in which AB = AC = 5cin and BC = 5.6 cm. If possible, draw its lines of symmetry.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 9

Question 8.
Construct a triangle PQR such that PQ = QR = 5 .5 cm and angle PQR = 90°. If possible, draw its lines of symmetry.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 10
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 11

Question 9.
If possible, draw a rough sketch of a quadrilateral which has exactly two lines of symmetry.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 12

Question 10.
A quadrilateral ABCD is symmetric about its diagonal AC. Name tire sides of this quadrilateral which are equal.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17A 13

Symmetry Exercise 17B – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
In each figure, given below, find the image of the point P in the line AB :
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B Q1
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 14

Question 2.
In each figure, given below, find the image of the line segment AB in the line PQ :
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B Q2
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 15

Question 3.
Complete the following table :
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B Q3
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 16

Question 4.
A point P (7,3)|is reflected in x-axis to point P’. The point P’ is further reflected in v-axis to point P” Find :
(i) the co-ordinates of P’
(ii) the co-ordinates of P”
(iii) the image of P (7, 3) in origin.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 17

Question 5.
A point A (- 5, 4) is reflected in y-axis to point B. The point B is further reflected in origin to point C. find :
(i) the co-ordinates of B
(ii) the co-ordinates of C
(iii) the image of A (- 5, 4) in x-axis.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 18

Question 6.
The point P (3, – 8) is reflected in origin to point Q. The Point Q is further reflected in x-axis to point R. Find :
(i) the co-ordinates of Q
(ii) the co-ordinates of R
(iii) the image of P (3, – 8) in y-axis.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 19

Question 7.
Each of the points A (3, 0), B (7, 0), C (- 8, 0), D (- 7, 0) and E (0, 0) is reflected in x-axis to points A’, B’, C’, D’ and E’ respectively. Write the co-ordinates of each of the image points A’, B’, C’, D’ and E’.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 20

Question 8.
Each of the points A (0, 4), B (0, 10), C (0, – 4), D (0, – 6) and E (0, 0) is reflected in y-axis to points A’, B’, C’, D’ and E’ respectively. Write the co-ordinates of each of the image points A’, B’, C’, D’ and E’.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 21

Question 9.
Each of the points A (0, 7), B (8. 0), C (0, -5), D (- 7, 0) and E (0, 0) are reflected in origin to points A’, B’, C’, D’ and E’ respectively. Write the co-ordinates of each of the image points A’, B’, C’, D’ and E’.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 22

Question 10.
Mark points A (4, 5) and B (- 5, 4) on a graph paper. Find A’, the image of A in x-axis and B’, the image of B in x-axis.
Mark A’ and B’ also on the same graph paper.
(ii) Join AB and A’ B’ and
find if AB = A’ B’ ?
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 23

Question 11.
Mark points A (6, 4) and B (4, – 6) on a graph paper.
Find A’, the image of A in y-axis and B’, the image of B in y-axis. Mark A’ and B’ also on the same graph paper.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 24

Question 12.
Mark points A (- 6, 5) and B (- 4, – 6) on a graph paper. Find A’, the image of A in origin and B’, the image of B in origin. Mark A’ and B’ also on the same graph paper. Join AB and A’ B’. Is AB = A’ B’ ?
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17B 25

Symmetry Exercise 17C – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
How many lines of symmetry does a rhombus have?
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17C 26
Question 2.
What is the order of rotational symmetry of a rhombus?
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17C 27

Question 3.
Show that each of the following figures has two lines of symmetry and a rotational.
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17C Q3
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17C 28

Question 4.
Name a figure that has a line of symmetry but does not have any roational symmetry.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17C 29

Question 5.
In each of the following figures, draw all possible lines of symmetry and also write the order of rotational symmetry:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17C Q5
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17C 30
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 17 Symmetry Ex 17C 31

Selina Concise Mathematics Class 7 ICSE Solutions