Punjab State Board PSEB 7th Class Maths Book Solutions Chapter 14 Symmetry Ex 14.2 Textbook Exercise Questions and Answers.
PSEB Solutions for Class 7 Maths Chapter 14 Symmetry Ex 14.2
1. Write the order of rotation for the following figures.
Solution:
(a) 2
(b) 2
(c) 5
(d) 6
2. Specify the centre of rotation, direction of rotation, angle of rotation and order of rotation for the following.
(i)
Solution:
Centre of rotation is O, direction of rotation is clockwise, Angle of rotation is 120° and order of rotation is 3.
(ii)
Solution:
Centre of rotation is P, direction of rotation is clockwise, Angle of rotation is 90° and order of rotation is 4.
(iii)
Solution:
Centre of rotation is O, direction of rotation is clockwise, Angle of rotation is 90° and order of rotation is 4.
3. Which of the following figures have rotational symmetry about the marked point (×) give the angle of rotation and order of the rotation of the figures.
(a)
Solution:
It has rotational symmetry, angle of rotation 180° and order of rotation 2.
(b)
Solution:
It has rotational symmetry, angle of rotation 90° and order of rotation 4.
(c)
Solution:
It has rotational symmetry, angle of rotation 72° and order of rotation 5.
(d)
Solution:
It has rotational symmetry, angle of rotation 60° and order of rotation 6.
(e)
Solution:
It has rotational symmetry, angle of rotation 90° and order of rotation 4.
4. Multiple choice questions :
Question (i).
The angle of rotation in an equilateral triangle is :
(a) 60°
(b) 70°
(c) 90°
(d) 120°
Answer:
(d) 120°
Question (ii).
A square has a rotational symmetry of order 4 about its centre what is the angle of rotation ?
(a) 45°
(b) 90°
(c) 180°
(d) 270°
Answer:
(b) 90°
Question (iii).
What is the order of rotational symmetry of the english alphabet Z ?
(a) 0
(b) 1
(c) 2
(d) 3
Answer:
(c) 2
Question (iv).
Which of these letters has only rotational symmetry ?
(a) S
(b) E
(c) B
(d) P
Answer:
(a) S
Question (v).
If the smallest angle of rotation is 90° then order of symmetry is ?
(a) 1
(b) 3
(c) 4
(d) 2
Answer:
(c) 4