Maths Topic 21 - Symmetry


 Line and rotational symmetry are commonly tested in 11+ and Selective School exams in the UK.

Examples

Example Question 1:

How many lines of symmetry do the following letters have?

(a) M,  (b) I,  (c) S,  (d) B,  (e) Z

Answers: (a) 1,  (b) 2,  (c) 0,  (d) 1,  (e) O

Explanations: See the diagram below

Example Question 2:

Which of the following shapes have rotational symmetry?

Answer: a, b & c

Explanation: A shape that has rotational symmetry can be rotated around its centre and fit back in its outline more than once. Every shape can fit back in its outline once but if that is all = no rotational symmetry. The order of rotational symmetry for these shapes is: (a) 5, (b) 6, (c) 3, (d) 1, (e) 1

Video Tutorials

Line Symmetry

Rotational Symmetry