Ex.14.3 Q7 Symmetry - NCERT Maths Class 7

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Question

Can we have a rotational symmetry of order more than $$1$$ whose angle of rotation is –

(i) $$45^\circ$$                (ii) $$17^\circ$$

Text Solution

What is known?

Angle of rotations

What is unknown?

The figures have rotational symmetry of order more than $$1$$ with the angles $$45^\circ$$ and $$17^\circ$$

Reasoning:

If the given angle is a factor of $$360^\circ,$$ then the figure will have rotational symmetry of order more than one otherwise not.

Steps:

(i) $$45^\circ$$ is a factor of $$360^\circ,$$ so the figure will have a rotational symmetry of order more than $$1$$ and there would be $$8$$ rotations.

(ii) $$17^\circ$$ is not a factor of $$360^\circ,$$ so the figure will not have a rotational symmetry of order more than $$1.$$

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