Rotational Symmetry Flashcards

All 6 cards in this deck

What does the order of rotational symmetry of a shape mean?

The number of times the shape looks exactly the same during one full turn ($360°$).

What is the order of rotational symmetry of a regular polygon?
e.g. a regular pentagon

The same as its number of sides.
A regular pentagon has order 5.

True or false? A shape with no rotational symmetry has rotational symmetry of order 0.

False. It has order 1, because every shape fits onto itself once in a full turn.

What are the steps to work out the order of rotational symmetry of a shape?
e.g. a rectangle

1. Put a pencil point (or finger) on the centre of the shape.
2. Turn the shape one full turn, counting each position where it looks the same.
3. That count is the order: a rectangle has order 2.

Through what angle must you turn a shape with rotational symmetry of order 4 for it to look the same?

$90°$, since $360 \div 4 = 90$.

Which quadrilateral should you draw for 'no lines of symmetry and rotational symmetry of order 2'?

A parallelogram that is not a rectangle or a rhombus.