The minimum order of rotational symmetry a shape can have is 1. A trapezium has rotational symmetry of order one. Some trapeziums have one line of symmetry. They are called isosceles trapeziums as ...

The minimum order of rotational symmetry a shape can have is 1. Some trapeziums have one line of symmetry. They are called isosceles trapeziums as they have 2 sides of an equal length like ...

(The line of symmetry can be constructed as a set of overlapping blue and red points.) Have the students explore drawing continuous symmetric shapes using vertical symmetry (Sketch 1) and oblique ...