Order of rotational symmetry of an isosceles trapezoid

Step by step

The question

Question: what is the order of rotational symmetry of an isosceles trapezoid?

1 Mark a corner

Put a dot on one corner, so we can follow it.

Then turn the shape about its center.

2 Turn and count

Turn it a little at a time.

It does not fit on itself, until the dot is back at the start.

That is after a full turn.

So it fits only 1 time.

3 The order

It fits only after the full turn.

So the order is 1.

We say it has no rotational symmetry.

Careful!

Every shape fits after a full turn.

So the order is 1, not 0.

4 Check

Let's check.

One full turn is 360 degrees.

Shared by 1, each turn is 360°.

1 turns of 360 degrees make 360 degrees: one full turn.

Right!

Let's look back.

First: mark a corner.

Then: turn and count.

Then: the order.

Last: check.