Punjab State Board PSEB 7th Class Maths Book Solutions Chapter 14 Symmetry Ex 14.3 Textbook Exercise Questions and Answers.
PSEB Solutions for Class 7 Maths Chapter 14 Symmetry Ex 14.3
1. In the following figures, find the number of lines of symmetry and angle of rotation for rotational symmetry.
Solution:
(a) Line of symmetry 3, angle of rotation 120°
(b) Line of symmetry 4, angle of rotation 90°.
2. Name any two figures that have both line of symmetry and rotational symmetry.
Solution:
Equilateral triangle and circle
3. If a figure has two or more lines of symmetry should it have a rotational symmetry of order more than 1 ?
Solution:
Yes, Square has four lines of symmetry and rotational symmetry of order 4.
4. Following shapes have both, line symmetry and rotational symmetry. Find the number of lines of symmetry, centre of rotation and order of rotational symmetry.
Solution:
(a) 3, centroid, 3
(b) 2, Intersection of diagonals, 2
(c) 6, centre of hexagon, 6
5. Some of the english alphabets have fascinating symmetrical structures. Which capital letters have just one line of symmetry (Like E) ? Which capital letters have a rotational symmetry of order 2 (Like I) ? By attempting to think on such lines, you will be able to fill in the following table.
Solution:
6. Multiple Choice Questions :
Question (i).
If 60° is the smallest angle of rotational for a given figure what will be the angle of rotation for same figure.
(a) 150°
(b) 180°
(c) 90°
(d) 330°
Answer:
(b) 180°
Question (ii).
Which of these can not be a measure of an angle of rotation for any figure.
(a) 120°
(b) 180°
(c) 17°
(d) 90°
Answer:
(c) 17°
Question (iii).
Which of the following have both line symmetry and rotational symmetry ?
(a) An isosceles triangle
(b) A scalene triangle
(c) A square
(d) A parallelogram
Answer:
(c) A square
Question (iv).
Which of the alphabet has both multiple line and rotational symmetries ?
(a) S
(b) O
(c) H
(d) L
Answer:
(b) O
Question (v).
In the word ‘MATHS’ which of the following pairs of letters shows rotational symmetry ?
(a) M and T
(b) H and S
(c) A and S
(d) T and S
Answer:
(b) H and S