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NCERT Solutions Class 7 Maths Chapter 14 Symmetry Ex 14.2

NCERT Solutions Class 7 Mathematics
Chapter – 14 (Symmetry)

The NCERT Solutions in English Language for Class 7 Mathematics Chapter – 14 Symmetry Exercise 14.2 has been provided here to help the students in solving the questions from this exercise. 

Chapter : 14 Symmetry

Exercise – 14.2

1. Which of the following figures have rational symmetry of order more than 1:

Solution –

(a)

So, the above figure has its rotational symmetry as 4.

(b)

So, the above figure has its rotational symmetry as 3.

(c)  So, the given figure has only one rotational symmetry.

(d)

So, the above figure has its rotational symmetry as 2.

(e)

So, the above figure has its rotational symmetry as 3.

(f)

So, the above figure has its rotational symmetry as 4.
By observing all the figures (a), (b), (c), (d), (e) and (f) have rotational symmetry of order more than 1.

2. Give the order of rotational symmetry for each figure:

Solution –
(a)

Let us take a point S on one end of the given figure. Rotating by 180°, S comes at other end and then again rotating by 180°, it comes at its original position.
∴ Order of rotational symmetry = =2

(b)

Let us take any point S in figure (1). It takes two rotations to come back to its original position.
∴ Order of rotational symmetry = = 2

(c)

Let us mark any vertex of the given figure. It takes three rotations to come back to its original shape.
∴ Order of rotational symmetry =  = 3

(d)

Order of rotational symmetry = = 4

(e)

∴ Order of rotational symmetry = = 4

(f)

The given figure is a regular pentagon which can take one rotation at an angle of 72°.
∴ Order of rotational symmetry = = 5

(g)

The given figure requires six rotations each through an angle of 60°
∴ Order of rotational symmetry = = 6

(h)

The given figure requires three rotations, each through an angle of 120°.
∴ Order of rotational symmetry = = 3

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